If you'd like to change your plan you can now do this easily through your account screen.

Note: Please do not copy and paste the video link into a new tab, but right click the link and select open link in new tab

If you are cancelling your subscription bear in mind that as soon as you downgrade your plan you will lose access to the members-only courses on the site, so you may choose to do this close to your next renewal point so you get maximum value from your subscription.