Ive been on a prepaid plan for years and not exactly sure how actual postpaid plans work right now. Have a phone i like but my parents want to get a family plan and want me to get in on it. Problem is i just want the plan and not the XR. If they do the buy 2 get 2 free XR deal, is it possible to activate the phone as mine, pull out the SIM and use it in my current T-Mobile phone? Just wondering if that, or some workaround, is possible? Many thanks for any help.