An elevator system includes at least one elevator, at least one call input device and a call controller. The call input device transmits a call to the call controller. For a transmitted normal operation signal, at least one elevator car of an assigned elevator is activated to drive to the call input floor by at least one elevator controller of the assigned elevator. In a peak-time mode of the elevator system, at least one main operation signal is transmitted to at least one elevator. For a main operation signal transmitted to an elevator, at least one elevator car of said elevator is activated to drive between at least two main operation floors by at least one elevator controller of said elevator.