Process a negative cash receipt against the prepayment.

1. Open Accounts Receivable, Main, Cash Receipts Entry, select the correct bank code and the next deposit number.
2. Enter the deposit amount as a negative amount. This should be the same amount as the prepayment, but with a negative.
3. Select the Customer and enter anything for the check number.
4. Enter the same negative dollar amount into Amount Received.
5. Click on the Lines tab, select the pre-payment invoice.
6. Click Accept