how do you unpair Apple watch if you can't access iPhone

I went to read how to set up a new iPhone (my old one died and I can't access it). The first step I noted was if paired with an Apple watch you should unpair it. However, the unpair instructions provide steps assuming you can access the iPhone that the Apple watch is paired to.

What are the options to unpair if you can't access the iPhone?

What happens it you can't do this?

Will the new phone link to the Apple watch if I sync it after setting up the new iPhone.

Thank you