The WordPress wp_list_pages() menus are really easy to customize.
Sometime developer want to add another link or to redirect a link to another page or URL from one of the pages.

For example I have a website and having wp_list_pages() with Home, About, Blog pages. Default that link will open page.php page with respective page that user clicked on.  But I want user to be redirect to my wordpress blog ie. by clicking on ‘Blog’ link.

How will I do that?
By default wordpress takes the Permalink for redirecting a page or post. And to get our own redirection we need to customize one wordpress function call ‘start_el()‘. ‘start_el()’ function does exist in ‘/site_directory/wp-includes/classes.php’ on line number 1168 (line number may change if additional code is there).

Get the page id first

$page_menu_id = 'menu_'.$page->ID;

Then check which page id(s) you want to filter

$pgURL = '';
if ( $page -> ID == '14' ) {
  #Disabling the active link
  $pgURL = 'javascript:;';
  #Redirecting blog page link to my wordpress blog
  $pgURL = '';
} else {
  $pgURL = get_page_link( $page -> ID );

$output .= $indent . '<li>';
$output .= '<a id="'. $page_menu_id .'" href="' . $pgURL . '" title="' . esc_attr(apply_filters('the_title', $page->post_title)) . '">';
$output .= $link_before . apply_filters('the_title', $page->post_title) . $link_after;
$output .= '</a>';