public function changeState($state)
    {
        $availableStates = $this->dbObject('Status')->enumValues();
        if (in_array($state, $availableStates)) {
            $this->Status = $state;
            return true;
        } else {
            user_error(_t('Reservation.STATE_CHANGE_ERROR', 'Selected state is not available'));
            return false;
        }
    }