Carrier Trade In Device May Not Be on Existing Installment Plan (ATT)

[Timenprayer]

Getting ready to preorder a new iPhone 14 Pro Max. My question - if we want to get the 36 months of ATT carrier credits, and we are trading in with Apple directly as noted here:

How does ATT even know that the traded in device was on an installment plan if we are upgrading a different line of service for the purchase of the iPhone 14?

 

[aok75]

You can’t trade in a phone that isn’t yours.

 

[Liberal]

How does ATT even know that the traded in device was on an installment plan if we are upgrading a different line of service for the purchase of the iPhone 14?

I would imagine that AT&T records the serial number or the IMEI and when you go to trade it in, whether it's Apple or anywhere else, that it shows there is still a lien on the phone.