As a chat room owner (someone who can update room settings, add members and deactivate the room), you can make a room member an owner or remove them as an owner.
To promote or demote a room member, use Chat Details. Click the i in the top right of your chat (Figure 1 and Figure 2):
Figure 1 Information Button
Figure 2 Chat Room Members
Click View members list to expand the list and hover over the person you want to update. Click … to promote, demote, or remove the member from chat (Figure 3):
Figure 3 Chat Room Members