Here are the steps you can follow to get this done.
- Go to the subscription details page and hit "Change Customer Details"(on the right panel). Screenshot below.
- Remove/modify the email address and click "Update Customer". (This is to ensure no email notifications are sent for that subscription).
- After you perform the operation, make sure to update the actual email address.
Note: This process is applicable to V1 & V2 email notifications.