Hello,
I want to change “Leave A Reply” title coming in comment section.
Inside comments.php file you should replace default call for comment_form which looks like this:
<?php comment_form(); ?>
With this code that adds comments_args where you can add other tweaks as well.
<?php
$comments_args = array(
// change the title of the reply section
'title_reply'=>'Write Your Comment Title here',
);
comment_form($comments_args);
?>
This is because this theme uses default comment form functionality without custom modifications, so instead of changing this string in WordPress core you can use this function.