This doesn't work because I want to CHANGE the bank info for the vendor. I already have them set up for bank transfer, which means you can't click on "Set up bank transfer" because it's already set up.

For any vendor that's already set up for bank transfer you get "Bank Transfer" text without a link. You see the "Set Up Bank Transfer" link ONLY if the vendor hasn't already been set up. So back to square one here.  I've attache a screen shot.