You can do the following to update your card on file:
Go to the More tab
Tap "Manage Membership" -> "Payment Method"
Add your new card information and hit Save (it will tell you if you've entered something incorrectly)
That's it. Your new card will be used for all future charges
If you are updating your credit card after a failed payment, you can typically just wait for the system to retry with your new card. But if you don't want to wait, we can manually charge your card to make sure it works.