Hello, i have a family plan with 4 lines. one line is eligible to upgrade and i plan on getting the iphone with that line. that particular line is my moms and she does not care for the iPhone. Does anyone know if i can upgrade her line and get the iPhone..... come home, cancel the unlimied data plan on her line, and add unlimited data plan on my line, and use my sim in the iPhone? Please let me know, thanks in advance!!