if you i bought a phone from someone and i was to call t-mobile to tell them that i got a new diff type of phone would they ask for the imei number?
Unless you're in the USA on a CDMA network, then all you do is to swap your T-Mobile SIM into the new phone. If the new phone needs a micro-SIM you can find instructions online showing how to cut it down to size, or you can order a micro-SIM (or get one free from a T-Mobile shop) and get your number ported from the old SIM to the new one (takes up to 48 hours). If the phone you've bought has been reported lost/stolen then it will get blocked and your SIM will not work on it. The phone will also not belong to you either, despite having handed over money for it. If you are on a CDMA network then you will have to tell T-Mobile the IMEI.
