You can remove a client from a Community by following the steps below
Go to Beyond Classes > Communities
Click into the Community > go to Class Roster
Click on the three dots next to the client's name and select the delete option
From there, you will be presented with two options to choose from:
Cancel existing reservations: Cancel the reservations for future classes within the Community
Expire pricing option: Moving the pricing option to "expired" so the client will no longer have access to resources within the Community