Adjusting or reversing a paid invoice creates credit notes. Reversing an invoice before payment reversal also creates credit notes. Apply the payment to a vendor invoices to remove the outstanding credit.

1. Make a backup of your data.
2. Go to Payables, Payments journal.
3. In the Pay To the Order of drop-down list, select the vendor or supplier.
4. Select the corresponding row of the Credit Note or Prepayment in the Payment Amount.
5. In the Paid By box, select your payment method. 

• • If paid by Cash, Cheque, or Direct Deposit, choose the account in the From field. Use the same account as the original
  • If paid by Cheque, Direct Deposit, or Credit Card, enter a label in the Source reference field

6. In the Cheque No. field, enter a label that indicates a refund or removal.   EXAMPLE: REF00321 or REM00321.
7. Verify all fields are correct.
8. Select Report, Display Payment Transaction Detail to review the journal entry for accuracy.
9. Click Process.
10. Verify the General Ledger and Vendor Aged reports are accurate. Credit note or prepayment will no longer appear on the vendor subledger.

How to apply a credit note
How to remove a credit note or deposit for a customer?