Did you add them to your account, or do they have an account and you became "friends" with them. If they have their own account and you became "friends," you can click on them and delete them.
If you originally added them, you can also click on them and delete them If they have no upcoming plans attached to their name and ONLY if they never had a magic band or card attached to their name. You must cancel or remove them from any upcoming plans to delete them. If they have a band or a card attached - you must call tech support to get these permanently removed (they will never be able to activate them again) and after tech support removes the magic bands or cards, you can delete them - I did this a month or so ago when I needed to remove my father in law.