You can cancel the order by specifying the "Order Acceptance Number" or the "Field For Internal Processing".
For more information, please refer to "System Interface Specifications for arrowhead - Data Format (Order/Notice) - 2.4. Cancel Order Message".
Please refer the following FAQ how to get "System Interface Specifications for arrowhead".
URL:
https://faqsd.jpx.co.jp/faq/show/3985?site_domain=en_application