Delete form responses
You can delete form responses by specifying any of the form properties as delete criterion. For example, you can delete only the form responses created by a specific user.
To delete a specific form response, you use the FormsManager class and call the Delete method passing the form entry as a parameter. The following code deletes a form response with the specified userId via Sitefinity CMS Native API:
In the code above, you first get an instance of the FormsManager class. Next, you filter response entries by getting the current user ID. You use LINQ query to filter the form entries and the GetFormEntries method of the FormsManager class. Finally, if the form response entry is not null, you use the Delete method to remove the response.