“If you ever forget your password or lose your iPhone, the Apple Watch offers a way to reset your device and erase all of your data. It goes without saying that resetting is the most drastic way to pair a new phone or access your smartwatch, but sometimes these things happen. If you’re looking to reset your watch, here’s how you can do it.
If you’ve forgotten your password, you can use your paired iPhone to erase your data and start fresh. To do this, open your watch app and go to the My Watch tab. From there, tap General > Reset > Erase Apple Watch Content and Settings. Tap to confirm, although you might need to input your Apple ID password to clear your data.
If you’ve lost your iPhone, on the other hand, you can perform a reset on the watch itself. It’s important that you keep the watch on its charger until you complete the following steps. Firstly, press and hold the side button until the Power Off option prompts on your screen. Keep your finger on the Power Off slider and then lift your finger. The Erase All Content and Settings prompt should appear, so tap that. Wait for everything to finish and then set up your account again.”