Problem with multi-factor authentication with multiple organizations

I am having the same problem, except that I was trying to switch to a new phone. I was able to add my home organization to the new phone but the partner organization's sign-in is still only on the old phone. Like the OP, I use my home organization's account to sign on to both. I have been forced to carry around my old phone at work all day in order to be able to sign in to the partner org's page. This is a hassle. I've scoured the web site and tried clicking everywhere I can find, and I haven't found any help online about this.