Sign in to your AT&T account
Go to your wireless account overview
Select the line you want to transfer
Choose Manage device or account options
Look for Transfer PIN or Number Transfer PIN
Request the PIN and follow the prompts
Use the AT&T app if the option is available there
Call AT&T customer support if you cannot find the option online
Make sure the account is active and you are the account owner or authorized user
Keep the PIN handy for your new carrier during the transfer process