Returns and debit notes

When a supplier's charge must be reduced — goods returned, an overcharge, a price agreed wrong — the correction is a debit note, the mirror of Sales' credit note, and never an edit to a posted invoice (1.6). Raise it against the supplier, line by line, with the reason in its notes, and allocate it to the purchase invoice it debits: on posting, the allocated amounts reduce what that invoice is still owed, and any remainder stands as credit with the supplier against future invoices. Tax unwinds by the same rules that raised it. As in Sales, the note settles the money; goods physically going back to the supplier are a stock event your warehouse records in Inventory (Chapter 5).