function cancelSubmission($submissionTicket, $comment = NULL) {
		if ($comment == NULL) {
			$cancelSubmissionRequest = new cancelSubmission ();
			$cancelSubmissionRequest->submissionId = $submissionTicket;
			return $this->submissionService->cancelSubmission ( $cancelSubmissionRequest )->return;
		} else {
			$cancelSubmissionRequest = new cancelSubmissionWithComment ();
			$cancelSubmissionRequest->comment = $comment;
			$cancelSubmissionRequest->submissionId = $submissionTicket;
			return $this->submissionService->cancelSubmissionWithComment ( $cancelSubmissionRequest )->return;
		}
	}