Find the reservation either in Dashboard section ( here we display only the reservations of the last 30 days) OR in the main Reservations section.

Click on the ResNumber.

In the popup window appearing you will have this view.


 Just beneath the Rejection section and the Rejection Button you will find a Yellow button called Billing Update Email

By pressing this button and automatic email to customer  will be send with a link to access the Modify Credit card section of the booking engine.

If you are connected with a payment getaway system , the Modify Credit card button is named Proceed to Payment and by pressing it client will be driven to payment getaway enviroment to proceed in direct payment of the amount required.

Here is a video with a quick guide:

https://www.screencast.com/t/pUVKNlsO