Hey, under my line I'm currently not eligible to upgrade to an iphone 4; however, my mom is eligible on hers. I was going to use her upgrade and simply put my SIM into the new iphone, while she kept her old phone. Problem is she doesn't have and or want a data plan, so I can't simply give her my old 3GS. But in order to order the iphone 4 I need to also buy a data plan. Will ATT let me cancel the data plan after I get the phone? I'm not really sure how the whole thing works, so any help would be appreciated. Thanks.