Ability to pull in Stripe information into HB, for existing customers to manage their own subscriptions

The video of "Moving existing customers to HB" doesn't address the detail of how existing customers can manage their subscriptions within HB.
I think this entails the ability to pull the customer credit card information from Stripe into HB.
Right now, I'm not clear on how existing members can manage credit card information (expiration dates, use a different card), upgrade/downgrade, or cancel their subscription.
I think this is important for the user experience of our loyal customers who've been with us since pre-HB.