You don't have to do anything, it will show as a box on your account because the law requires it for some reason or so I am told by Tivo.
I had to open a second account because I had somewhere around 10 boxes that I no longer owned still showing, I just wanted to clean it up.
"Luck is the residue of design"
1 S2 Tivo w/lifetime retired
1 HD Tivo Lifetime
1 Roamio OTA only
60" LG Plasma
60" Vizio 1080P
36" LG HD