Please read this article to know how to reset Form Publisher on your Google Form.
1. Open Form Publisher Status
Click the add-ons icon, then Form Publisher > Form Publisher Status:
2. Reset Form Publisher settings
Once done, click 'Reset settings' twice, and confirm by clicking 'Yes':
If you open Form Publisher again, you'll notice that all your settings menus have been erased, and replaced by 'Get Started' (exactly as if it was it is the first time you configure Form Publisher on your Form):