We currently allow you to link only one bank at a time to any given Stockpile account. If you want to change your linked bank, send a quick email to firstname.lastname@example.org that says "Cancel my bank link so I can set up a new one."
Why are we being so restrictive? It's because money launderers and other bad guys love moving money in from one account and out to another. It's a favorite trick in their playbook, and as a U.S. financial institution, we have to guard against it.
Still, we don't want to make it hard for you, so we're working on a new way to give you a way to link multiple bank accounts without letting the bad guys in. We'll let you know when it's ready!