$parentPage = get_page_by_path('services');

$query = new WP_Query([
    'post_type' => 'page',
    'post_parent' => $parentPage->ID,
    'posts_per_page' => -1,
    'orderby' => 'menu_order',
    'order' => 'ASC',
]);

if ($query->have_posts()) {
    while ($query->have_posts()) {
        $query->the_post();

        echo '';
        the_title();
        echo '';
    }
}

wp_reset_postdata();