Hello,
To make the changes please create or download child theme from https://catchthemes.com/blog/create-child-theme-wordpress/
then copy the content-sidebar-yourpagelayout.php . (yourpagelayout is the layout of your website, if you have sidebar to the right use content-sidebar-right.php or if you have it on the left use content-sidebar-left.php and so on)
Then paste the php file on the child theme’s root directory, finally open the file and find and replace <?php comments_template(); ?>
to
<?php
$comments_args = array(
'title_reply'=>''
);
comment_form($comments_args);
?>
If you have any queries and want a swift response please visit the themes official forum
https://catchthemes.com/support-forum/forum/simple-catch-public/
regards,
bplv