<thr:in-reply-to ref="<?php the_guid(); ?>" href="<?php the_permalink_rss() ?>" type="<?php bloginfo_rss('html_type'); ?>" />
<?php else : // This comment is in reply to another comment
$parent_comment = get_comment($comment->comment_parent);
<thr:in-reply-to ref="<?php the_guid(); ?>" href="<?php the_permalink_rss() ?>" type="<?php bloginfo_rss('html_type'); ?>" />
<?php else : // This comment is in reply to another comment
$parent_comment = get_comment($comment->comment_parent);