Removing WorpDrive from a site is done in the "WorpDrive Backup" section of the iControlWP control panel.
- click on WorpDrive Backup from the left-hand menu
- click on "Manage Sites" for the site that you want to remove WorpDrive from
- then click "Remove" (see the screenshot below)
- enter your iControlWP account password to confirm the removal and click the final button to remove WorpDrive.