The customer object is not editable as part of the subscription with the one exception that you can change the payment method on the subscription to a different one attached to the account.
Customer account ID. Clicking on this will allow you to drill down to the customer details.
Customer name on the account.
All payment methods for the account will be listed here click on the triangle to expand. The current payment method will be indicated in the top bar in green. To assign a different payment method select the "Assign" button next to that payment method and click update.
Each payment method block includes: Payment Type, Account Holder, Customer Specified Type, Customer Specified Description, Payment Method Holder Name and Address. In addition the relevant masked payment method details are displayed.
Date through which the current entitlement runs. This is typically updated after each successful billing event.