How to reset Apple Watch without the using app

Hi soha410,

Thanks for posting in Apple Support Communities! If you forgot the passcode on your Apple Watch, reset it to factory settings using the steps below from the article If you forgot your Apple Watch passcode:

1. "Put your watch on its charger and keep it there until you complete these steps.
2. Press and hold the side button until you see the power button in the upper-right corner of the display.
3. Press and hold the Digital Crown until you see Erase all content and settings.
4. Tap Reset, then tap Reset again to confirm.
5. Wait for the process to finish, then set up your Apple Watch again. When asked, restore from a backup."

This will allow you to access the Apple Watch again and successfully update the software. Here's some additional resources for updating:

Update your Apple Watch

Update your iPhone or iPad

Cheers!