This function provides a way to cancel specific jobs, or specific delivery items within a job. This function submits a request for the cancellation, and a "success" response merely indicates that the request was successfully sent to the EasyLink system, not necessarily that the deliveries have actually been canceled. Since the time period when this cancellation can take effect can be small, deliveries may still complete before the request is acted upon. Cancellation is more likely to succeed for scheduled jobs or submissions that have large documents for processing.