Is it possible to change the numbers on an iPhone sim card?

My friends mom gave me her iPhone 4s and I currently have an Iphone 3gs. The sim card from the 3gs is too big so I was wondering if i could somehow change the number on the 4s sim card to my number from home or would it be better to just go to the at&t store?

No, you can't do that, but you may be able to cut the SIM to fit the phone. Do a Google search on cutting SIM cards to mini-SIMs and you should have no problems.

Follow the link… It will show you how to exactly cut your sim to micro sim.