BuddyPress.org

I’ve never done this but you’re going to have to modify your database either completely manually or write some PHP to do this.

You’ll be looking in both the wp_signups table and also the wp_users.

I’m not sure if they are both relevant but if you look at your users and the current situation you should be able to figure it out.

Be careful though, take a DB dump if you’re not sure what you’re doing.