It's good to see you here in the Community, @mmarchand.
Editing a completed payroll is done via payroll correction. Thus, I encourage reaching out to our QuickBooks Payroll Team to help you void or delete the processed payroll and recreate it.
To reach them, you can follow the steps below:
Sign in to your QuickBooks Online account.
Click the Help button.
In the QuickBooks Assistance chatbox, select Talk to a human and choose I still need a human.
Select Contact Us.
You might also want to read these resources to learn when to cancel or edit payroll checks in QuickBooks Online: