The editorial comments appear in the edit page of a post, within the Editorial Comments box at Nelio Content Tools, as you can see here:
You can delete an editorial comment during few minutes after submitting it. To do so, you must be the submitter of the comment. Just hover the mouse over the comment and you’ll see the Delete option as shown in the image above.
If you select that option, the comment will be deleted (once you confirm) and will disappear from the conversation.