Apple instructions to unlock iphone 12 AT&T

Let’s review a few things:

• Once unlocked, it will be unlocked forever
• One option is to have AT&T activate the eSIM in the phone; you can actually do that by going to Settings/Cellular and tap Convert to eSIM - this will free up the SIM slot for a foreign SIM card; then if you want turn off the AT&T side of the dual carrier feature.
• AT&T has an excellent International roaming plan. Once you enable it you pay $10 a day for any day where you use your AT&T number or data when roaming using your “home” voice, text, and data plan, with a maximum of $100 a month. This is competitive with getting a foreign pre-paid SIM, which are pretty expensive.
• As it is a dual number phone you can get a local pre-paid SIM and still keep the AT&T number active for calling back to the US or receiving calls from the US. This will be cheaper than using the prepaid foreign SIM
• And, if you have Wi-Fi calling enabled on the AT&T account there is no charge or usage for Wi-Fi calls using the AT&T number.

AT&T’s instructions are correct. You need to reinstall iOS to bypass carrier lock. Here are Apple’s instructions→How to unlock your iPhone for use with a different carrier - Apple Support. If you have a different SIM card you can try inserting it. But if you don’t you don’t really want to be in a different country when you find out that the phone has not been unlocked.

Because his iPhone is currently locked to AT&T and if he gets overseas and enters a different SIM he will get a paragraph telling him he cannot use that SIM until the carrier lock is removed.

Her is a correction to the instructions that AT&T gave you, in number 3 do not restore your iPhone from your backup, set it up as a new device and you will get a message saying, "Congratulations, your iPhone has been unlocked." Then Restore from your backup. And in step 1 I usually back up both to the computer as well as iCloud.