I want unpair from old iPhone and pair with new iPhone. How?

Follow the steps in the support document you came from to unpair it from your old iPhone.

Then follow the steps here to pair it to the new one: link-> How to pair your Apple Watch with a new iPhone - Apple Support

If you mean unpair Apple to pair with new phone, this link explains how --> How to pair your Apple Watch with a new iPhone - Apple Support

Congrats on your new phone! You can follow the instructions in this support document to pair your Apple Watch with your new phone: https://support.apple.com/en-us/HT205189

I tried to pair my i7 to my new XR but it did not finish I seem to be stuck in settings on Update apple id settings . I sing in but can't get any further!! Any ideas