I would suspect that if you purchased directly from Apple and purchased AppleCare at the same time that they would have transferred it for you -- but I may be wrong.
You could go to the following site and see if it shows that you have AppleCare on the new device: https://checkcoverage.apple.com/
If it doesn't show the device is covered, you could use the information below and see if they can help you options other than cancelling. From How to manage your AppleCare plan - Apple Support
When you're ready to cancel your AppleCare plan, contact Apple Support and tell the advisor that you need help canceling the AppleCare plan.