How do you enable and reset your Apple ID and password if it’s in a reset watch that is linked to an Apple ID
How?
Apple Watch SE
If the Watch is linked to an Apple ID which you do not control, you cannot reset it. If you obtained the Watch from another user, please advise them to follow the advice provided in What to do before you sell, give away, or trade in your Apple Watch, or buy one from someone else - Apple Support.