If you wish to alter this payment date, you can do so using the subscription replacement feature.
Why Change the Subscription Payment Date
There are some scenarios where, at the client’s request, you may wish to offer a change in the subscription payment date.
For example: the client purchased a monthly subscription on the 16th, but requested that it be changed to the 1st of the month so they can budget for it more effectively.
How to Set Up A Payment Date Change With the Subscription Replacement Feature
This tutorial will show you the steps required to allow your clients to change their subscription payment dates.