Credit passes can be customized in the respective customer’s profile. You can either search for the customer via "Customers" in the menu or use the general search bar at the top right to search for the customer name. Now select the credit pass on the customer’s page.
The transaction overview of the credit pass will open, and you can click on the "Product details" button on the right.
A new pop-up window will open in which you have to click on the "Show" button under "Product details".
Here you can edit almost every setting you adjusted when you created the credit pass. For example, you can change the number of credits or the expiration date.
The changes made will only apply to the product of the selected customer.