How to Unpair Apple Watch without iPhone?

On your Apple Watch, tap Settings > General > Reset > Erase All Content and Settings. This will reset your Apple Watch to the factory settings.

To unpair and erase watch and remove Activation Lock

From a web browser,sign in to iCloud.com with your Apple ID.

Go to Find iPhone.

Click All Devices at the top of the screen.

Click your Apple Watch.

Click Erase [device]. Select Next until the device is erased.

Click Remove from Account.

Then come back here because erasing a watch doesn't remove the activation lock,which is required for a trade in.;