Centralized facility reservations, where all space requests are reviewed and approved/denied by a central scheduling authority (an individual or department), is one end of the scheduling process spectrum. EMS products provide all the tools a central scheduling office needs to book rooms, reserve resources and coordinate meeting/event-related services.
At the other end of the spectrum is a fully self-service scheduling environment, where people either have access to EMS on their own computer or use Virtual EMS, smart phones, kiosk units or other access methods to book their own rooms, resources, etc. without any approval process. Here too, EMS provides all the functionality a self-service operation needs to work effectively.
Most organizations utilize a combination of the two approaches. For example, smaller rooms that typically are used for simple events might be available to reserve in self-serve mode, where larger rooms that hold more complex events (with catering, equipment, etc.) might only be available through the reservations office.