Upgrading DAZN NFL game pass subscription to 'Ultimate' via iTunes

I want to upgrade my DAZN NFL game pass subscription to ultimate. I don't see how to do that.

This is what DAZN said to do, but it didn't work.

Via iTunes on your computer:

• Go to 'Account'.
• Select 'View my Account'.
• On the Subscriptions page, select 'Manage'.

[Edited by Moderator]