Final answer:
A member off-duty should be notified of changes via email or phone call, as these methods are direct and provide timely communication.
Step-by-step explanation:
If a member is off-duty when a change is made, they should be notified by C) Email or D) Phone call. These methods allow for quick and direct communication, ensuring the member receives the necessary information in a timely manner. The use of email is especially prevalent in professional settings for its convenience and ability to provide a written record of the notification.