Erasing Apple Watch from iPhone after water damage

I can’t pair a new Apple Watch ⌚️ now! My old watch is still connected to my phone. It has to pair with it again to erase all content. What do I do?

[Re-Titled by Moderator]

Original Title: I got my Apple Watch wet and it slowly died. I put it in a bag of rice 🌾 no help, it’s dead ☠️ how do I erase it from my phone now , so I can buy another apple watch and pair it ?