I signed my XBox One into a friends Plex server. A few weeks later I decided to setup my own. I have the Plex server working but cannot find where in the XBox One Plex app to disconnect it from the old server and connect to the new server / Plex pass account.
I am away from my Xbox Right now, but I believe when you open the settings menu (the hamburger button with 3 lines on the controller and then settings from the popup) the first subsection is account which should have button to log out.
If I am wrong I’ll have to wait till I get back to my Xbox to give more precise instructions.