function delete_order($force_delete = true, $id = false)
 {
     $id = $id ? $id : $this->id;
     if ($force_delete) {
         wp_delete_post($id);
     } else {
         wp_trash_post($id);
     }
     //Delete associated ticket instances
     $args = array('post_type' => 'tc_tickets_instances', 'post_status' => 'any', 'post_parent' => $id);
     $ticket_instances = get_posts($args);
     foreach ($ticket_instances as $ticket_instance) {
         $ticket_instance_instance = new TC_Ticket_Instance($ticket_instance->ID);
         $ticket_instance_instance->delete_ticket_instance($force_delete);
     }
 }
<?php

$tickets_instances = new TC_Tickets_Instances();
$page = $_GET['page'];
if (isset($_GET['action']) && $_GET['action'] == 'delete') {
    if (!isset($_POST['_wpnonce'])) {
        check_admin_referer('delete_' . $_GET['ID']);
        if (current_user_can('manage_options') || current_user_can('delete_tickets_cap')) {
            $ticket_instance = new TC_Ticket_Instance((int) $_GET['ID']);
            $ticket_instance->delete_ticket_instance();
            $message = __('Attendee and Ticket data has been successfully deleted.', 'tc');
        } else {
            $message = __('You do not have required permissions for this action.', 'tc');
        }
    }
}
if (isset($_GET['page_num'])) {
    $page_num = (int) $_GET['page_num'];
} else {
    $page_num = 1;
}
if (isset($_GET['s'])) {
    $attendeesearch = $_GET['s'];
} else {
    $attendeesearch = '';
}
$wp_tickets_instances_search = new TC_Tickets_Instances_Search($attendeesearch, $page_num);
$fields = $tickets_instances->get_tickets_instances_fields();
$columns = $tickets_instances->get_columns();
?>
<div class="wrap tc_wrap">