You can create new roles or change permissions to the various roles under Administration -> Permissions
Note that users will automatically assume new roles as they create and delete channels (eg. once an account with user permissions creates a new room, they will have owner permissions for that room).
There may be times when you want to manually change a users' role, or add additional roles to that user. For example, if you have a user who initially is created with guest permissions (the default) and you want to upgrade them to regular user role so that they have more capabilities (such as creating rooms).
This is also useful for transitioning ownership of a room from en exiting employee to a new owner, or for adding a Moderator to a room.
To change permission for a user: