I have reset my iPhone. But now, am unable to reset my Apple Watch so that I can pair it with my phone again.

On a computer, go to iCloud.com and sign in with your Apple ID.

Go to Find Iphone.

Select All Devices, then click your Apple Watch.

Click Erase Apple Watch.

Select Next until the device is erased.

Click the remove button next to your Apple Watch.

I am unable to reset my watch. I do not see watch listed in iCloud account too. Watch is unpaired from phone.

Unpair and erase your Apple Watch - Apple Support