It’s possible to use imel2 to unlock phone carrier

If you’re asking if you can unlock one IMEI on a phone while the other one is still locked to AT&T, the answer is no.  Both IMEIs on a dual SIM phones are either locked or unlocked together.  You’ll also likely need to make the request with the IMEI that’s using the AT&T SIM, because that’s the IMEI that AT&T will have registered in their database.  If you haven’t used IMEI2 with AT&T, you’ll probably get an error that the number isn’t in their database.

Please can someone reply to this post ? 

I think you can but it is probably safest to use the IMEI that you are using for your ATT service for the phone you have paid off in full and otherwise meet their requirements.

Hello Folarin, we're here to help you with your unlock phone inquiry.

When submitting a device unlock request, it usually takes a few minutes to approve your request, however it can also take up to 48 hours.

If you do not have a wireless phone account, you have to select Confirm request on the email we sent you. Be sure to check your Inbox, Spam, and Junk folders as the email may have be sent to one of those folders. If you do not see an email, you will want to resubmit the request after the 24 hours. 

Check to make sure all unlock eligibility requirements are met when submitting your request.

Your device:

• Is an AT&T phone or device and isn’t active on another AT&T account.
• Has a paid-off installment plan:
  • Paid through your monthly bill: Submit your unlock request at the start of your next bill period.
  • Paid off early: The wireless number assigned to the device must be active for at least 60 days. Wait 48 hours after you make your final payment to submit your unlock request. Learn how pay off your installment plan.
• Was paid in full when you bought it (it was not purchased on an installment plan). You must wait 60 days from your purchase date to submit an unlock request.
• Doesn’t have a past-due account balance. Make a payment to bring your account current. It will take 24 hours for your payment to post.
• Hasn’t been reported as lost, stolen, or involved with fraud.
• Is an AT&T Prepaid phone that has had paid service for at least six months. You must submit your unlock request using the most recent version of the AT&T Device Unlock app.

Before purchasing a device from a non-AT&T authorized dealer or sites like eBay, make sure the seller performs the unlock request.

In some instances, you will have to contact the seller to perform the request. If the device was purchased by another provider, they should have online resources to unlock the device.

There is no code for unlocking an iPhone. If approved Apple unlocks the phone via their activation servers when the phone connects to them. 

Once Apple’s servers are updated, then the SIM locked status will change in the settings on your phone. If you're using a non-AT&T SIM, make sure that you’re connected to Wi-Fi when you install the SIM, so the phone can connect to the Apple servers if it isn’t already unlocked.

Let us know if this helps. Reach back out to us if you have any other questions.

Jeff, AT&T Community Specialist