You can cancel your credit card on file any time by going to your "My Payments" (1) tab. Next click on the little arrow next to "Pause your subscription" (2). This will show a dropdown menu where you can select "Update your credit card." Updating your payment method will affect how your payment is charged for your next billing cycle.
*This setting can only be changed through the desktop browser and not the mobile browser or mobile app.
If your account is already paused you will need to go to the Course Catalog and click "Subscribe to All" again. See this Article for more info.