Paper Deletions' requests are available only for assignments created upon Turnitin.com
Once a deletion request is approved, papers will no longer be recoverable.
Requesting a Permanent Deletion
Locate the paper that you'd like to delete at your assignment.
Check next to the Author column of the paper you'd like to delete.
Select the Delete button and choose Request permanent deletion.
A form will appear where you'll also be asked to give a reason for the deletion to help your Administrator in approving your request, then you are asked to type out the word 'Delete' and finally use the Confirm button to send the request to your Turnitin Administrator.
Turnitin will send you a notification that your request was sent to the Turnitin administrator to review it , and another to inform you if it has been approved or rejected in the Messages inbox.