Switching to XFINITY, what do I do with AT&T's ONT box?

Cancelled my U-Verse fiber plan for Xfinity's fiber. Since it's Rona season, the Xfinity technician will be giving me a self-install kit for setting up the internet connection and will only handle the outside wiring.

I'm in a 2 bedroom apartment so I think there's only 1 point of access for installing internet, which is covered by AT&T's ONT box. The fibers are wired through a location where all the apartment units share the same wall in the floor plan. No idea how to remove that ONT (Edited per community guidelines), would I just be able to wire my Xfinity stuff through it or how do I uninstall it? There's no useful guides online.