Can I delete the existing payroll system and reset it up?

I can share some information about deleting and resetting your payroll, zhua1216.

At this time, you can only delete your entire data in QuickBooks Online and start over with new books if your account is less than 60 days. This is available for QuickBooks Online Plus, Essentials and Advanced. If it’s already beyond, I suggest cancelling your old account and creating a new one. To learn more about wiping your data clean in QBO and starting over, refer to this article: Delete your data and start over in QuickBooks Online.

The option to reset or purge only your existing payroll data will be a great addition to the current features that we have, so I'll take note of it. Feel free to provide comments from within the account. These are the steps:

1. Go to the Gear icon and select Feedback.
2. Provide your product suggestion.
3. Click on Next to submit feedback.

For additional details on how to provide feedback to enhance the program, see this article: How do I submit feedback? 

Check out the following article for more information on how to set up payroll and complete your payroll setup tasks: Get started with QuickBooks Online Payroll. 

Let me know if you need further information about deleting and restarting your QuickBooks Online (QBO). I'm always here to help. Have a great rest of the day!