To knock off a specific amount from an invoice (total invoice 10,000.00 and to knock off is 1,000.00), you need to create a payment this way: (to receive Payment total 5,000.00 split into 1,000.00 and 4,000.00)
Go to Transaction File Maintenance, select Add.
Key in payment 1st line Credit Debtor 1,000.00.
Key in payment 2nd line Credit Debtor 4,000.00.
Key in payment 3rd line Debit Bank 5,000.00 to receive payment.
Make sure all reference no bear the same OR (official receipt) no,
Save and accept the transaction.
At the Knock-off menu, pick - 1,000.00 amount to match against the invoice amount of 10,000.00.
Save and accept the knock-off.
The remaining $4,000.00 can be used to knock off another transaction.