wife's daughter on tmobile contract (been with them 6 years)and got me thinking, as her mother want to get out of virgin mobile (slow data etc)i ask her when she could upgrade and she said end of January i was wondering if she got a new phone with upgrade would her mother be able to have her old phone and add a sim to it and used that on prepaid ??? or if she got a new phone her mother could even have new phone as she does like the one shes got now and might want to keep it i know its a longshot but????.