private void ClearAllSchedule()
    {
        ReservationManager reservationManager = GameObject.Find("MapUtil").GetComponent <ReservationManager>();

        reservationManager.ClearAll();

        foreach (ShipController ship in priorityQueue.queue)
        {
            ship.schedule = null;
            ship.status   = ShipStatus.Scheduling;
        }

        foreach (ShipController ship in waitList.queue)
        {
            ship.schedule = null;
            ship.status   = ShipStatus.RedSignal;
        }
    }