Q: Request Carrier Unlock without being Customer

Hi all, is it possible to request a carrier unlock without being a AT&T costumer?

All forms, documents and web sites where I could request the unlock require a wireless number or contract number.. I don't have one, I bought the phone with lock and want to remove it for the usage of my current provider (contract nearly expired).

Maybe I will become a ATT costumer later.. depends on AT&T communication culture. 🙂