Hello,
Rooms don’t have comments enabled in WP hotelier. It is a custom post type.
So what you’re asking is possible only modifying the room template and adding the support for comments. Unfortunately I can’t help you with that so this is something you need to integrate yourself.
To add support for comments you can use this snippet in your theme:
https://pastebin.com/raw/E5WuQbFS
Then place this line somewhere in wp-hotelier/templates/single-room/content-single-room.php. Remember that you can override that file in your child theme (https://docs.wphotelier.com/article/66-override-template-files).
<?php comments_template(); ?>
You will need to style the form of course.
Hope this helps.
Best Regards,
Benito