Unlink tv from old user

[QuartzK]

My mom recently divorced this guy and gave me their old Tv, but he’s still has the tv linked to his home. Every time I try make edits it tells me request to join HIS home. So how would I unlink his device from the Tv

[Matteo1]

Is it an Apple TV?

[Ashepherdson]

I assume the tv has Chromecast built in,  best bet is to factory reset the tv and resetup Chromecast.