Can you go by a phone in a different state go home and have that area codes number?

My weirdo ex got a phone in new york,and i guess ativated it there, so he has a new york number, and he lives in LA can he go home to LA and keep his new york number, or does he have to stay in new york to keep it?Can you go by a phone in a different state go home and have that area codes number?
He can keep the number for as long as he keeps the account active. I use to sell phones in a town in Arizona that got a lot of out of state visitors in the winter and we could even give someone a phone number with an area code from their state even though they were buying the phone in AZ. This isn't as big of a deal anymore since so many different types of phone services offer some free or unlimited long distance so not sure if you can still do this or not. There isn't any rule, law or whatever that makes you have to have a phone number with the same area code as the place you live. I even had a AZ phone number for the longest time when I moved to Oklahoma.Can you go by a phone in a different state go home and have that area codes number?
He can keep his NY number or he can change it and he can still keep his phone.



If he keeps it, he will be paying roaming charges and his friends may not appreciate for a long time paying long-distance charges to call him.