How do I amend a payroll run? The taxes haven't been filed

We can definitely assist you in amending the payroll you've processed for your employee who no longer works for you, CH721.

In QuickBooks Online (QBO), you have the option to edit, delete, or void a paycheck. In this case, we can delete the paycheck and process the employee's final paycheck to cover their remaining wages. To edit, delete, or void the paycheck, please follow these steps:

1. Go to the left menu and click on Payroll. 
2. Choose Employees. 
3. Select the Paycheck list.
4. Find the paycheck you want to amend.
5. In the Action column, click the Print drop-down. 
6. Select Edit, Delete, or Void. 
7. Press Edit, Delete, or Void to confirm. 

I've attached a video for your visual reference: 

For more information on editing your payroll, you can check out this article: Edit, delete, or void employee paychecks. 

Once done, follow the steps in this article to create their last paycheck: Create final paychecks for terminated employees. Then, update their employee status in your payroll service.

Moreover, refer to this article to run payroll reports, view information about your business and employees: Run payroll reports. 

If you have any other questions or need further assistance amending an employee's paycheck or any Payroll-related concerns, feel free to leave a comment below. Have a great day!