the_content to the_excerpt

How I can change the_content to the_excerpt, when there is no line with the_content words. Please help.

<?php
/**
 * Index Template
 *
 * This is the default template.  It is used when a more specific template can't be found to display
 * posts.  It is unlikely that this template will ever be used, but there may be rare cases.
 *
 * @package Origin
 * @subpackage Template
 */

get_header(); // Loads the header.php template. ?>

	<?php do_atomic( 'before_content' ); // origin_before_content ?>

	<div id="content">

		<?php do_atomic( 'open_content' ); // origin_open_content ?>

		<div class="hfeed">

			<?php if ( have_posts() ) : ?>

				<?php while ( have_posts() ) : the_post(); ?>

					<?php do_atomic( 'before_entry' ); // origin_before_entry ?>

						<div id="post-<?php the_ID(); ?>" class="<?php hybrid_entry_class(); ?>">

							<?php do_atomic( 'open_entry' ); // origin_open_entry ?>

							<?php if ( current_theme_supports( 'get-the-image' ) ) {

								if ( is_sticky ( $post->ID ) ) {

									get_the_image( array( 'meta_key' => 'Thumbnail', 'size' => 'single-thumbnail', 'image_class' => 'featured' ) );

								} else {

									get_the_image( array( 'meta_key' => 'Thumbnail', 'size' => 'thumbnail', 'image_class' => 'featured' ) );

								}

							} ?>

							<div class="sticky-header">

								<?php echo apply_atomic_shortcode( 'entry_title', '[entry-title]' ); ?>

								<?php echo apply_atomic_shortcode( 'byline', '<div class="byline">' . __( '[entry-published] · [entry-author] · [entry-terms taxonomy="category" before=""] [entry-edit-link before=" · "]', 'origin' ) . '</div>' ); ?>

							</div><!-- .sticky-header -->

							<div class="entry-summary">

								<?php the_excerpt(); ?>

								<?php wp_link_pages( array( 'before' => '<p class="page-links">' . __( 'Pages:', 'origin' ), 'after' => '</p>' ) ); ?>

							</div><!-- .entry-summary -->

							<?php do_atomic( 'close_entry' ); // origin_close_entry ?>

						</div><!-- .hentry -->

					<?php do_atomic( 'after_entry' ); // origin_after_entry ?>

				<?php endwhile; ?>

			<?php else : ?>

				<?php get_template_part( 'loop-error' ); // Loads the loop-error.php template. ?>

			<?php endif; ?>

		</div><!-- .hfeed -->

		<?php do_atomic( 'close_content' ); // origin_close_content ?>

		<?php get_template_part( 'loop-nav' ); // Loads the loop-nav.php template. ?>

	</div><!-- #content -->

	<?php do_atomic( 'after_content' ); // origin_after_content ?>

<?php get_footer(); // Loads the footer.php template. ?>