Can I switch out of a T-Mobile family account?

Each one of those phones has its own contract. You would need to determine when your specific contract ends. You can not keep your own number. Companies do not port numbers to phones within in the company again. After your contact ends your number instantly goes into limbo until another t-mobile customer gets it. Once your contract ends you simply walk away

Is it locked to your network? And you want to use to any other network globally? If yes, then you need to unlock your mobile according to the network you reside , Its a paid service. first find out your mobile phone IMEI number. You can find this by typing in *#06# and then hitting the enter o rsend key on your phone . This number is completely unique to your phone and will be used to generate or calculate an unlock code for your mobile.Then the unlock code here using unlock code specified in it you can proceed unlocking your mobile.