AppointmentItem.IsConflict Property (Outlook)
Returns a Boolean that determines if the item on the local computer is different from the copy on the server. Read-only.
Whether or not an item is in conflict is determined by the state of the application. For example, when a user is offline and tries to access an online folder the action will fail. In this scenario, the IsConflict property will return True.
This property does not indicate whether the appointment item has a time conflict with another appointment in the calendar.