Hi Sharon,

You will need to rollback the payroll and then mark as leaver and re-run.

If you are on Paysuite you can rollback by going to Employees > Run Payroll Drop-down > Payroll Settings > Pay Calendar and Rollback on the action drop-down from the current period. 

If you are using the QuickBooks Online payroll you rollback by going to Employees > Payroll > Pay History > Select the period and delete by selecting the trash icon. 

Thanks