Grocery CRUD simple DUPLICATE row method

public function manage()
{ 
try{
$crud = new grocery_CRUD();
$crud->set_table('office');
$crud->set_theme('datatables');
$crud->add_action('DUPLICATE', '', 'cms/offices/duplicate','ui-icon-plus');
$output = $crud->render();
$this->load->view('cms/office_view.php', $output); 

}catch(Exception $e){
show_error($e->getMessage().' --- '.$e->getTraceAsString());
}
}

function duplicate($primary_key, $row)
{
$query = $this->db->get_where('office', array('office_id' => $primary_key));
if ($query->num_rows() > 0)
{
$res = $query->result();
$row = $res[0];
}
$data = array(
'ordinal_number' => $row->ordinal_number+1,
'ordinal_text' => $row->ordinal_text,
'office_name' => $row->office_name,
'TBRC_P_ID' => $row->TBRC_P_ID,
'start_date' => $row->start_date,
'end_date' => $row->end_date,
'community_TBRC_ID' => $row->community_TBRC_ID,
'tradition' => $row->tradition,
'office_TBRC_R_ID' => $row->office_TBRC_R_ID,
'description' => $row->description
 );

 $this->db->insert('office', $data); 

header('location:/cms/offices/manage');
exit;
}