If you are administrator in a chat room you may 'ban' or eject a person from the room for an extended period of time if they become disruptive.
To ban a user from the room you must use the admin console. To access the admin console click on the menu icon at the upper right of the chat room window (it looks like 3 horizontal lines). Now select 'show admin console' from the menu that appears.
Click on 'bans & bounces' in the blue header of the admin console window. The recents 'tab' should be highlighted in the white header near the top of the window. A list of users that have recently joined the chat room will show in the list view.
To ban a user, hover your mouse pointer over their name in the list, and click on the 'ban' button that appears to the right of their name. You will see their name move to the right side list view of 'banned members;.
If you want to 'un-ban' a person, hover over their name in the banned members list, and click on the 'X' that appears to the left of their name. The ban will be removed and the user will be able to re-join the room.
You can also use the 'clear all bans' button (seen under the banned members list view) to remove all bans at the same time.