I am going to Italy and I need to have a local cell phone
( I have ATT 4s iPhone). How does the swapping of the SIM cards work?
You need to contact AT&T to see if you're eligible to have your iPhone unlocked to use another carrier's SIM card. If you're NOT eligible, you'll either need to purchase a local pay as you go phone in Italy, or purchase a cheapie unlocked phone here in the US.