Got my 2012 iPad with AT&T LTE after spending a year with my iPad2 with AT&T 3g. Upon signing into my wireless account on the iPad, there was an option to sign in as an existing iPad account owner. Doing so enabled me to transfer the remaining balance of my 3g account to LTE for no additional charge. I also have the option of going from 2 to 3 gb/month for an additional $5 after the current cycle is completed. Logging onto account data on the iPad2 requires a new sign in, so presumably a new owner can sign on and use the 2 without requiring a new SIM card. When I first bought my iPad2 a year ago, I swapped models with another 3g owner and both of us were required to get new sims from our local AT&T store.