$this->_from_participant_id = CRM_Utils_Request::retrieve('pid', 'Positive', $this, FALSE, NULL, 'REQUEST');
$this->_userChecksum = CRM_Utils_Request::retrieve('cs', 'String', $this, FALSE, NULL, 'REQUEST');
$this->isBackoffice = CRM_Utils_Request::retrieve('is_backoffice', 'String', $this, FALSE, NULL, 'REQUEST');
$this->_from_participant_id = CRM_Utils_Request::retrieve('pid', 'Positive', $this, FALSE, NULL, 'REQUEST');
$this->_userChecksum = CRM_Utils_Request::retrieve('cs', 'String', $this, FALSE, NULL, 'REQUEST');
$this->isBackoffice = CRM_Utils_Request::retrieve('is_backoffice', 'String', $this, FALSE, NULL, 'REQUEST');