Once you manually key in a guests credit card, it is retained for that reservation.
If the bill does not yet have a credit card retained, the above box will show on the bottom right of the bill just below the remaining balance. When you retain a credit card, do not enter any dashes or spaces. Also please be sure to pay special attention to the format for the expiration date.
After you click "Add Credit Card" the system will attempt to validate the card and then, if successful, retain it for this bill. Once a credit card has successfully been retained the system will display the following message.
Retain Multiple Cards
If you need to retain a second (or 3rd, etc.) credit card, choose New... from the drop-down box to the right of "Credit Card" after you have selected credit card as the new payment type. A popup box will ask for the new card information.The newest cards are always at the bottom of the drop-down list.