Check Post & Page Parameters or get_page_children().
<?php
global $post;
$args = array(
\'post_type\' => \'page\',
\'posts_per_page\' => -1,
\'post_parent\' => $post->ID,
\'order\' => \'ASC\',
\'orderby\' => \'menu_order\'
);
$parent = new WP_Query( $args );
if ( $parent->have_posts() ) : ?>
<?php while ( $parent->have_posts() ) : $parent->the_post(); ?>
<div id="parent-<?php the_ID(); ?>" class="parent-page">
<h1><a href="<?php the_permalink(); ?>" title="<?php the_title(); ?>"><?php the_title(); ?></a></h1>
</div>
<?php endwhile; ?>
<?php endif; wp_reset_postdata(); ?>