My BIL's phone bill is really high so we offered to let him join our family plan. He is leaving Verizon for ATT. ATT told me he could keep his phone but had to call the carrier after the line is cancelled and request an "unlock" to make it usable across carriers. The Verizon lady I talked to (we got pricing for family plans there too, ATT won BY FAR) acted like she had no idea that that was possible.

Has anyone done this? His phone is newer so he wants to keep it. It's an Android.