How to get AT&T service on a Sprint iPhone 5?

I bought a wiped Sprint iPhone 5 from a friend and wanted to know how I would go about getting AT&T service on said phone.

I think you would just go into an at&t store and ask them to switch it. They may charge tho

You need to get the Sprint iPhone 5 unlocked before you can use the phone on AT&T, that phone has SIM slot for GSM carriers. If you need help with getting the phone factory unlocked, mail me for more info.