Inform Apple of the purchase of an old iPhone 11 Pro with AppleCare plus warranty?

Here is a link to the terms - the seller has to inform Apple:

https://www.apple.com/legal/sales-support/applecare/applecareplus/docs/applecareplusnaen.html

The important paragraph:

10. Transfer of Plan

For Single-Pay Plans only, you may

make a one-time permanent transfer of all of your rights under the Plan

to another party, provided that: (i) you transfer to the other party the

original proof of purchase, the Plan Confirmation, the Plan’s printed

materials and this service contract; (ii) you notify Apple of the

transfer as instructed at support.apple.com/en-us/HT202712,

and (iii) the other party accepts the terms of this service contract.

If you financed the purchase of your Plan through a Payment Plan

Provider, the transferee must assume and comply with all payment

obligations of the transferor, and any failure to do so by a transferee

shall immediately trigger the applicable cancellation provisions as

described in Section 9. When notifying Apple of the transfer, you must

provide the Plan Agreement Number, the serial number of the Covered

Equipment, and the name, address, telephone number and email address of

the new owner.