Hi rruzo24,
Thank you for using the Apple Support Communities! I understand you have questions about your existing AppleCare+ coverage when trading your phone in for a new device. I can help answer this for you.
Your AppleCare+ plan is specific to your iPhone serial number. This means the plan cannot be transferred to a different phone. If you do choose to cancel your plan, you may qualify for a refund based on the percentage of the unexpired AppleCare plan coverage, minus the value of any service that may already have been provided: How to manage your AppleCare plan - Apple Support.
If you would like to discuss the option above, reach out to Apple Support using this link: Contact - Official Apple Support.
Thank you for your post!
Take care.