When you enroll on the waitlist for a course, you are instructing MyMadison to enroll you in the next available spot in that course (think of waiting in line outside a club that is at capacity).

You may want to enroll in a course as a backup for a course you are waitlisted for. However, if the two courses are offered at the same time, this presents a problem. When the waitlisted course opens up, MyMadison will attempt to add you, but will run into a time conflict with your backup course, and the enroll attempt will fail. Therefore, you will need to give MyMadison permission to swap the courses. To do this:

1 - Enroll in your backup class FIRST. This seems counter-intuitive, but it will work. If you have already enrolled in the waitlisted course, you'll need to drop it. This will send you to the back of the line, but it's the only way to make this work.

2 - Using the swap function (view a tutorial here), swap the backup course for the course you would like to be on the waitlist for.

3 - When a spot in the waitlisted class opens, MyMadison will obey the swap instruction, drop the backup class, and enroll you in the waitlisted class.