Click Customer list

Search for customer & click their name

Locate the membership > click the dropdown menu to the right > and click Edit

Update the renewals left figure to the needed expiration timeline. If you put a 0, it will make this month the customers last month.

After clicking save, the subscription should now say 'Expires' instead of 'Renews on'

If you'd like to edit the expiration date, click the same dropdown menu, then Edit again, and change the expiration date to be any day you choose. Notice how the field now says 'Expires on'.