Just switched to a lower-resolution TV and get no picture. How to adjust settings on Xbox One with no picture?

I just moved. Before the move, the Xbox One was hooked up with a 1080 tv. In the new place, i'm hooking it up to a 720 tv. When I do, I get a message on my TV that it's receiving a signal it can't use. (1080 on a 720 tv). So now how do I get the xbox one to change it's video out settings if I can't see the screen??

Submitted by douggold11 | #Specialdealer Special Offer Online Shopping Store 2016