BuddyPress.org

There is typically no turning back when you choose either subdirectories to subdomains, but it can be done manually, it’s just a lot of work.

It’s going to require manual editing of your database via phpMyAdmin, finding/replacing all of the places where url’s are now incorrect, and you will also need to change some settings in wp-config.php accordingly,

<?php define('VHOST', 'yes'); ?> to start with, and your domains and paths too.