Okay my youngest sister recently lost her phone. We had it shut down and now she has a new phone which she bought from a friend but we still need a new sim card to fit the phone. The contract and bill are in my younger sister's name. (They share a plan) Does she need to be present to get the new sim card or can just like me and her or her and my mom be present with the account number or something to get the new card?
You can easily give ATT a call before you go; they need to provide you with a new SIM card, since the old one has been deactivated and the contract is still valid. While you can not use the phone without a card, you still pay for the contract with ATT. Make sure you get that sorted out also with them when you go there. They could give you some credit for the days you had no service because you had no SIM card. If it is a shared plan, that might not be the case, though, but it never hurts to ask.