How to close out retro event notifications for terminated employees.

We have a need to close out retro event notifications for terminated employees. We tried adding an override parameter: Earliest Retroactive Processing Date with our Payroll Process Configuration Group where the date is +1 greater than the date for the employee with an awaiting process event. We added this process configuration group to our recalculate payroll for retroactive changes flow. This did not close out the event. We also tried the same process for active employees and also had no success.