function do_LOCK()
 {
     global $post;
     if ($post) {
         $current_user = wp_get_current_user();
         include_once "wp-admin/includes/post.php";
         $current_owner = wp_check_post_lock($post->ID);
         if ($current_owner && $current_owner != $current_user->ID) {
             nocache_headers();
             status_header(423);
             die;
         }
         nocache_headers();
         parent::http_LOCK();
         die;
     } else {
         nocache_headers();
         status_header(404);
         die;
     }
 }