You can change your enrollment status (withdraw) or reduce your time commitment (audit) for a course through your Dashboard.
You can access your dashboard by clicking on your profile photo at the top left corner.
Once you access your dashboard, you can scroll down to your "Current Courses" section. Look for the specific course you would like to make a change to and click on the gear icon at the bottom right of the course card. If there is an option to audit the course, you will see "Audit" and "Withdraw" as your options.
In this example, if you choose to withdraw - selecting "Withdraw" will lead to the following alert.
Once selected, you will notice that the course will not display on your dashboard.