my friend recently got a window's phone. now she hates it. i have two lines one of which im not using. so i have a 4s on one line and a 5 on the other im using the iphone 5. my question is. can she swap her sim card from her window's phone into my iphone 4s? and if so will it still be linked to my AT&T account? like will she be using my data, messaging, minutes or will putting her sim card in the iphone 4s automatically make it so when she uses the phone all the messaging, data, minutes she uses get's charged to her account? please help!