Hi, So today I got the dreaded text message that for my convenience I was upgraded to a smartphone data plan from my dumbphone one. I am not very happy about my data cap, especially now that we have free tethering, so here is where I'm at now. My sister has an iphone that has the unlimited data plan. I called AT&T asking to switch our data plans so she has the 200 MB smartphone plan and I have the unlimited smartphone plan. They told me they can't switch the plan as it is no longer supported. But If I were to switch sim cards with her, other than changing phone numbers, would this solve our problems? I assume so as I know many of you have switched from iphones just by moving the sim card. Thanks.