Welcome to the Community, @office270. I can share with you some insights about amending the pay date or pay schedule in QuickBooks Online (QBO).
Once a schedule has already been assigned to your employee and was used in payroll, revising the schedule or last pay date is currently unavailable. What you can do is reassign your employee to another pay schedule first.
Sign in to your QBO account.
Go to the Gear icon, then select AccountandSettings.
Tap on Payroll.
In the Payroll section, select PaySchedule.
Select Editschedule.
Update the pay schedule's info and select Savepayschedule or select Delete to remove it.
Alternatively, you may create an unscheduled payroll check for this entry.
For more tips about modifying the pay schedule in QBO, you can open these links: