To update a member's payment amount or date, visit your All Customers section > Participants > Programs > and click on the student's name. This will open their Program registration page.

For this structure, click the pencil icon next to "Membership Fee":

From here, either update the Membership fee amount or the next payment date or both:

PLEASE NOTE: for Open Enrollment Structure memberships, when editing payment date, the system will adjust the recurring payment schedule moving forward. (For example: if you adjust a monthly payment from December 1st to December 15th, the following payment will be on January 15th).

For other membership types, click the Payments tab on the left side of the Program registration page:

Then click on any upcoming payment to edit/update it:

This includes applying a credit to it, editing it, and deleting it permanently.