While we enroll students automatically for you, we currently lack the ability to drop them from the course, so you'll need to do that yourself when a student drops, withdraws, etc. From the Control Panel, click on "Remove User From Course" in the "User Management" pane. Search for the student by last name and check the box next to their name. Type "Yes" (Note the capital "Y"! It's important!) in the box at the bottom and click "Submit."