This problem has happened to my bf - he didn't want his iphone 4 upgrade so he sent a sealed, unactivated iPhone 4 that he received from the online Apple Store to a family member overseas (he is keeping the contract and line for his 3GS). We have just learned that the iphone 4 has to be activated with my bf's SSN and zipcode - which he is sort of alright about doing - but he is concerned what happens to the SIM cards during the activation. Is it obligatory that the iPhone 4 SIM takes over the 3GS line - and the 3GS SIM becomes inactivate - or can you stop the activation process early so that the iPhone 4 micro-sim does not actually take over the line??? In summary, my bf is concerned about being without a phone line (and also a bit uneasy about a SIM card from his line being on the loose overseas). Can anyone help?