Answer: When you open a prepaid sale voucher in modification mode, using the display or report, it will ask you for the card number. You must tender in order to exit. You cannot exit without tender.
Note: If you close the application by pressing the keys ctrl+alt+del or restart the computer, then the card will be blocked. Then you must unblock the card manually.
For more details please visit: http://www.rancelab.com/help/fr6_prepaid_card_transaction.htm