You can sort (ascending or descending) your roster by Student Name or Student ID; you can also sort by which students are currently logged into your room.
Click on Rooms
Next, find the room with the roster you'd like to remove and click on the Roster menu.
Click one of the roster headers to sort by that category (e.g. Here, Student Name, Student ID). To switch between ascending and descending order, click the blue arrow that appears to the right of the header name.