You can check the status of your Portal Premium Membership and the date it is due to auto-renew by following these instructions:

1. Open the Systems Settings app on your Mac.
2. Click on your name/Apple ID located at the top left of the window and sign in if requested.
3. Click “Media & Purchases”.
4. Click Subscriptions “Manage”.
5. Select Portal “Edit” from your list of subscriptions. 

Here you will be able to view the status of your Membership, including the date it is due to auto-renew.

If you do not see Portal listed this most likely means you do not have an active Portal Membership.

Apple processes payments 24 hours before the end of a billing cycle, which means if you did want to cancel your Portal Premium Membership you must do so no later than 24 hours before the renewal date of your current Membership.