Reverse an invoice with a credit note in SamBooks
12 min read
How to cancel or reduce an invoice already sent to the SDI with a credit note: full or partial reversal, numbering, sending, and effects on due dates and stock.
What it's for
Once an electronic invoice has been transmitted to the SDI (the Italian Interchange System), it can no longer be edited or deleted: it is a finalised document. If you later find an error, a customer returns goods, you grant a rebate you hadn't planned for, or you need to cancel a wrong invoice altogether, the tool for that is the credit note: a TD04 document linked to the original invoice that reverses all or part of its amount.
Before you start
You can only issue a credit note once the original invoice has reached a final status: "SDI accepted", "Delivered", "Delivery failed", or "Paid". The original must also be a genuine invoice, not already a credit or debit note itself: you cannot issue a variation note on another variation note.
When a correction is enough, and when you really need a credit note
Before opening the reversal dialog, check what stage the invoice is at:
- The invoice is still "Draft" or "Ready" (never sent to the SDI): no credit note is needed. Correct it directly with "Edit", or remove it with "Delete" — at this stage it has no fiscal effect yet.
- The invoice is "Sent to SDI" and you're waiting for the outcome: there's nothing to do, neither correcting nor reversing. Wait for the receipt (usually a matter of minutes).
- The invoice is in a final status ("SDI accepted", "Delivered", "Delivery failed", or "Paid"): here the credit note is the only tool. The document can no longer be edited or deleted — you can only reverse it, in full or in part.
- The invoice was "SDI rejected": be careful, you CANNOT issue a credit note here — the system refuses it, because the invoice was never actually finalised. If the mistake is in your company's own data, fix it in Settings and resend the same invoice. If the mistake is in the document itself, a rejected invoice currently cannot be edited or deleted: contact support before issuing another document.
Step by step
1. Open the invoice you want to reverse
Open Sales invoices in the left-hand menu, find the document in the "Outbound invoices" list and open it by clicking the row. Check in the header that the status is one of the final ones listed above.
2. Click "Reverse"
In the detail page's action bar, if the status allows it, you'll find the "Reverse" button (an icon of a document with a minus sign) next to "Debit note". Click it.
3. Choose between a total or partial reversal
The "New credit note" dialog opens, with the description "Reversal of invoice {number}. Select the lines and amounts to reverse; leave everything full for a total reversal." Every line of the original invoice is pre-loaded, selected, and at its full value: if you leave it as is and confirm, you get a total reversal (the "Total reversal" badge at the top of the dialog).
For a partial reversal:
- clear the checkbox on any line that isn't part of the reversal;
- on the lines that remain, lower the "Qty" field if the customer only returned part of the goods;
- or type a lower value directly in the "Amount" field if you're granting a rebate on a value rather than a quantity — note that as soon as you touch Amount, the Qty field is disabled, because a manually entered amount always takes precedence over the automatic calculation.
The badge switches to "Partial reversal" and the totals (Taxable amount, VAT, Document total) at the bottom of the dialog update live as you work.
4. Enter the reason for the reversal
Fill in the required "Reason for the reversal" field (up to 200 characters): for example "returned goods", "rebate", "cancelled a wrong invoice". Without a reason, the confirm button stays disabled.
5. Create the credit note
Click "Create credit note". SamBooks generates a new TD04 document in "Draft" status, linked to the original invoice, and takes you straight to its detail page. You'll see the message "Credit note created as a draft."
6. Send the note to the SDI
A credit note is a document in its own right: as long as it stays in draft, it has no fiscal effect at all. To complete it, you send it to the SDI exactly like any other invoice — the "Send to SDI" button, a confirmation step, an automatic check of the file, and transmission. The whole procedure is described step by step in Send an invoice to the Interchange System (SDI): it applies word for word to a credit note as well.
An alternative path: starting from "New invoice"
You can reach the same credit note without going through the original invoice's detail page: from Invoices, click "New invoice" and, as the document type, choose "Credit note" (it sits in the "Variation notes" group, together with "Debit note"). The form then shows a "Reference invoice" field, with the picker "Choose the invoice to adjust": only invoices already sent to the SDI show up here ("A variation note is issued against an invoice already sent to the Interchange System"); if you don't have any yet, you'll see "No referenceable invoice (requires invoices sent to SdI)". Once you pick the invoice, the button becomes "Proceed": clicking it opens the exact same "New credit note" dialog described above.
Numbering and document series
Like any invoice, a credit note is created without a number: the sequential number is only assigned when it's actually transmitted to the SDI, never before. Unlike ordinary invoices, though, credit and debit notes are numbered on a dedicated series with the code "NC", kept separate from the numbering of regular sales invoices — SamBooks creates it automatically the first time you need it, with nothing to configure on your end. This separation keeps the numbering of your regular invoices clean and gap-free. Documents issued before this rule was introduced remain on their original series.
Effects on due dates and accounting
- Payment schedule: a credit note does not create a due date of its own; it reduces (nets against) the outstanding balance still open on the original invoice. You can see this on the original invoice's "Document" tab, under "Payments & due dates", in the line "Linked credit notes: −{amount}".
- Journal entry: like any invoice, once the credit note receives its number (that is, once you send it to the SDI) SamBooks automatically creates the linked journal entry; you'll find it on the "Accounts" tab of its detail page.
- Exporter quota (plafond): if the lines you're reversing were invoiced VAT-free to a regular exporter (nature code N3.5, based on a letter of intent received from that customer), the reversal automatically restores, proportionally, the quota that letter of intent had used up.
Where you see the link to the original invoice
On the credit note's own detail page, open the "Document" tab: in the "References" card you'll find a "Linked invoice" badge with the number and date of the invoice you reversed. It works the other way round too: on the original invoice's detail page, same "Document" tab, the "Linked credit notes" line tells you how much has been reversed in total, even if you've issued more than one note against the same invoice.
Heads up: a credit note does not put stock back in the warehouse
This is the detail that catches people out the most: reversing an invoice is an accounting and fiscal operation. It reduces the amount owed, updates the payment schedule, and possibly restores an exporter quota — but it does not generate any stock-in movement in the warehouse. If a customer has genuinely sent goods back to you, the credit note on its own does not put that stock back on the shelf: unless you act elsewhere too, your inventory will stay short of those items even after the reversal, and you'll only notice at year-end stocktaking, when the numbers don't add up.
For a goods return, the path built for exactly this is the Returns module (the "Returns" entry under the Logistics section of the sidebar): starting from the original invoice, it generates, in sequence, a return delivery note — the document that actually loads the goods back into stock — and the linked credit note, plus an optional shipping label for the pickup. If your reversal is only a rebate or an amount correction, with no physical return involved, the "Reverse" button described in this guide is exactly right on its own, and there's nothing else to do. But if stock is genuinely coming back, remember to adjust your inventory yourself — with a stock-in movement or an adjustment in the warehouse module — whenever you don't go through Returns.
Constraints and messages you may see
- "A variation note cannot be issued on another note (TD04/TD05). Issue it on an invoice such as TD01/TD24/…" — you tried to reverse a credit note or debit note that was already issued: this isn't allowed.
- "Reversal amount for line N exceeds the original amount" — you entered a reversal amount on a line that is higher than what was originally invoiced: correct it.
- Partial reversal not available on a fee note with welfare-fund contribution — if the original invoice is a professional fee note carrying a welfare-fund contribution, SamBooks only allows a total reversal: you cannot reverse only some of the lines.
- The "Reverse" button doesn't show up at all — check that the invoice status is one of the final ones listed above, and that it isn't already a credit or debit note itself.
Need to charge more instead? The debit note (TD05)
If, instead of a return, you need to add an amount to an invoice already issued — a balancing charge, a price adjustment, an ancillary cost you forgot to bill — the matching tool is the debit note (TD05): same starting point in the detail page's action bar (the "Debit note" button, next to "Reverse"), but here you add new lines instead of reversing existing ones. It works as a mirror image of what's described here: you pick the lines to add, enter the reason for the charge, create the document as a draft, and send it to the SDI.
Ask Sam
You can get the same credit note from Sam's chat too, without opening any dialog. For example: "create a credit note on invoice 45/2026, full reversal", or for a partial return: "reverse 2 units of the ballpoint pens line on invoice 45/2026, the customer returned them". Sam creates the note as a draft exactly as the "Reverse" button would — partial reversals included — and leaves it ready for your review. Even when you ask Sam, sending it to the SDI stays a separate step that you confirm yourself: Sam never transmits a credit note without your explicit confirmation.
If something goes wrong
- The "Reverse" button isn't there: the invoice hasn't reached a final status yet, or it's already a credit/debit note, or you're looking at the wrong invoice.
- "Original invoice in status '…': a credit note is only allowed on invoices in a final status": same cause as above — the system is confirming it explicitly.
- You created the note and then forgot about it: it stays in "Draft" forever and has no fiscal value. You'll find it among your active invoices by filtering on "Document type" = "Credit note": send it whenever you're ready.
- The invoice you want to reverse is "SDI rejected": this isn't possible, by design — a rejected invoice never reached a final status. Read the rejection reason on the document: if it concerns your company's data, fix it in Settings and resend the same invoice.
- You spotted a mistake on the credit note after you'd already sent it to the SDI: once transmitted, a credit note is as final as a regular invoice, and you cannot issue a note against a note. The remedy therefore goes through a new document on the original invoice — typically a debit note that brings the amount back to the correct figure: talk it through with your accountant.
Frequently asked questions
How do I create a credit note in SamBooks? Open the invoice you want to reverse (it must be in a final status), click "Reverse", choose a total or partial reversal, enter the reason, and click "Create credit note". The note is created as a draft: send it to the SDI like any other invoice to make it effective.
A customer returned goods to me — what do I do? Issue a credit note against the original invoice — total if the whole order came back, partial if it's only some lines or quantities. Remember that a credit note alone doesn't put the goods back in the warehouse: use the Returns module if you want the physical return recorded together with the reversal.
Can I reverse only part of an invoice? Yes. In the "New credit note" dialog, clear the lines that don't apply, or lower the quantity or amount on the lines that remain: the badge switches from "Total reversal" to "Partial reversal" and the totals recalculate immediately.
Does a credit note need to be sent to the SDI? Yes, always: it's created as a draft and has no fiscal effect until you send it, following the exact same path as a regular invoice.
Does the warehouse update automatically when I issue a credit note? No. A credit note is an accounting operation: it doesn't generate any warehouse movement. If physical goods came back, record that separately — through the Returns module, or with a stock-in movement or an adjustment in the warehouse module.
Can I issue a credit note against another credit note? No: the system refuses a reversal of a note (TD04 or TD05). A variation note can only be issued against a genuine invoice.
How do I grant a customer a rebate with no goods returned? In the reversal dialog, keep the relevant line selected, leave the quantity untouched, and type a lower value directly in the "Amount" field: that's a partial, amount-based reversal, with no need to lower any quantity.
Why can't I find the "Reverse" button on my invoice? The invoice probably hasn't reached a final status yet (it's still a draft, "Ready", or "Sent to SDI" awaiting a response), or it's already a credit or debit note itself.