You can do it in two ways:
1).
$defaults = array(‘sort_column’ => ‘menu_order, post_title’, ‘menu_class’ => ‘menu’, ‘echo’ => true, ‘link_before’ => ”, ‘link_after’ => ”,’exclude’=>’11,12′);
$args = wp_parse_args( $args, $defaults );
$args = apply_filters( ‘wp_page_menu_args’, $args );
2). <?php wp_list_pages(‘exclude=11,12’ ); ?>