Check that the device is eligible for unlock
Pay off any remaining device balance
Make sure the account is in good standing
Confirm the phone is not reported lost, stolen, or involved in fraud
Get the phone number and device IMEI
Submit an unlock request through the AT&T unlock portal
Follow the email confirmation link or instructions
Wait for AT&T approval and processing
Insert a SIM card from another carrier to complete the unlock
Restart the phone if needed
Contact AT&T support if the request is denied