Before canceling AmpMac, make sure your data, repositories, credentials, DNS changes, and any production dependencies have been moved or retired. Once you are certain the system is no longer needed, follow the cancellation or non-renewal process available in your account.
If your goal is only to stop future billing, disabling automatic renewal or allowing the service not to renew may be sufficient. If you want the service fully closed, review the options in your account or contact support.
Do not cancel a live system until you are sure nothing still depends on it.