Confirm the iPhone is paid off and not under contract
Make sure the account is in good standing
Check the carrier’s unlock policy
Contact the carrier’s customer support
Request an unlock for the iPhone
Provide the IMEI number when asked
Wait for the carrier to approve the unlock
Insert a new carrier’s SIM card after approval
Connect the iPhone to Wi-Fi or a computer
Complete any activation steps if prompted
Restart the iPhone if the unlock does not appear immediately