Technologically, yes.
BUT as it is, ABSOLUTELY NOT.
The phone is locked to the ATT network, and will only function with ATT and MVNOs using the ATT network.
It will have to be unlocked to run on T-Mobile. Even then, it wont work as well as a T-Mobile 635.
Return that 635, get a T-Mobile one, it'll save money, hassle, and the likelihood of it never being unlocked.