This is the area in which a supervisor has the most day-to-day involvement.The key to avoiding problems is to set clear expectations and to address infractions firmly and fairly. For example you can let the employee know that you expect them to request approval for any leave at least 48 hours in advance, and that anything outside of that time frame would be considered an unscheduled absence. You can set an expectation that each employee can have no more than two unscheduled absences in a three month time period.It would then be up to the the supervisor to monitor and reinforce the expectations.
You should discuss your expectations with your manager and consult with Employee Relations to ensure that your expectations are reasonable and in conformance with pertinent MOU’s.