I'm sorry to see you go, but I want to make it as easy as possible for you when you are ready. Login to your parent account and find the Account menu link.
On your Account page you'll see a "Manage Subscription" button that will allow you to update or cancel your subscription. You can then restart your subscription any time from the same page.
On the next page, look for the "Cancel Plan" button:
That's all there is to it!