My iPhone 3G has the glass broken, and instead of getting it fixed I'm going to upgrade to the 3GS. I don't have an upgrade available, but I'm in a family plan and my mother does have her upgrade available. When ordering online it asks you to select a rate plan, obviously the only choice being the $30 one or the $45 enterprise one. I already have that plan for my current iPhone, and she doesn't have an iPhone so won't need that plan. Is there anyway around this? Can I simply select that plan and then once I get the 3GS put in my sim card and cancel her data plan that I had to select when ordering the iPhone online? Any help would be appreciated, thanks!