1. Log in to your Client Area
2. In the yellow Your Active Products/Services box in the center of the page, click on the Name of the subscription that you want to cancel (ie. Wordpress Startup, not your domain name)
3. Click the Log in to Plesk link in the left Actions menu.
4. In the center of the new Plesk window, click on the Hosting & DNS link
5. Below that, click DNS Settings