The CancelDeliveryNote POST API call is used to cancel a previously issued delivery note by submitting its unique identifying details. This ensures the cancellation is formally registered and acknowledged by the relevant tax authority system (myDATA).Request Format:Headers:APIKey (string): A valid API key used to authenticate the request.Body (JSON):vat (string): The VAT number of the entity requesting the cancellation.mark (string): The unique identification number (MARK) of the delivery note to be canceled.notificationEmails (array - string): The emails of the recipients that you want to notify about the cancellation of the delivery note.Functionality: When a valid request is submitted, the system processes the cancellation of the specified delivery note. The response provides confirmation along with detailed metadata related to the original document and the cancellation action.Validations for cancelDeliveryNote:Disallows cancellation if not a Delivery Note (type 9.3)Disallows cancellation if already canceledDisallows cancellation if not submitted via ProviderResponse Fields:mark: The MARK of the original delivery note that was canceled.cancellationMark: A new unique identifier representing the cancellation action.authenticationCode: A code confirming the authenticity and integrity of the cancellation.myDataResponse: The raw response or message from the myDATA system.status: Indicates the outcome of the cancellation request (e.g., "Success", "Failed").series: The series code of the original delivery note.number: The document number of the original delivery note.dateIssued: The date when the original delivery note was issued.erpQRCode: A URL returned by myDATA that redirects to the official document entry on the IAPR (Independent Authority for Public Revenue) website.success: Boolean flag (true / false) indicating whether the cancellation was successful.