We have several subscription options (each is monthly, but give more or less features to the customer depending on which one they purchase)

How can a customer change from one type to the other?  (i.e.  From the user prospective, they are “upgrading their subscription”)

We do not want to force the customer to re-enter their credit card information at all - they will simply “upgrade” and “confirm” (i.e. *without canceling the first and signing up for a second*)

I have the subscription hash, can I send that with a new cart item to have that put into the current subscription?

I’m testing some samples - and will report findings, but I wanted to find out if anyone else has come across this need.

Thank you!
-Mark