From the main menu, go to Point of Sale:
- Enter the customer,
- At the bottom of the window, click the green "Account" button,
- Select one or more invoices,
- You can quick select all the invoices by click the above the check boxes,
- Enter the Deposit amount without the discount,
- Click the Generate rebate button to generate the discount,
- Click the Accept button to continue and finalize the payment.