Customize the cancel_comment_reply_link

Although the post says,1 year ago, but maybe someone needs to know how, so I will share my knowledge.

You may create a file, named comments.php in your active themes’s root directory and make changes to it:

<h3>Comment form title</h3>
<p><?php cancel_comment_reply_link(); ?></p>
<form id="commentform" action="<?php echo site_url(); ?>/wp-comments-post.php" method="post">
    <textarea name="comment" id="comment"></textarea>
    <?php
        comment_id_fields();
        do_action('comment_form', $post->ID);
    ?>
</form>