I can not to do it, because I not have AT&T user's account and I'm not US citizen.
You can call to AT&T team support or fill unlock request form: https://www.att.com/deviceunlock/c
It's absolutely free service.
I will pay 40$ for each successful unlock. Need to unlock 30pcs iphones,
Thank you. If you will have questions, please contact to me
LOCKED/UNLOCKED status you can check here: