What is the issue with your iPhone please?
Could you please describe your issue please?
Did you mean it is locked with a passcode and you don't know what it is?
sorry I am not an expert in changing carriers. So I would opt out here so that a different expert might be able to help you. You will receive an email reply once another expert replies.
Hi there and welcome
To clarify, you want to move from Sprint to AT&T with the iPhone correct?