How should you address a foreign military member if you forget their rank?

Addressing a foreign military member when you forget their rank should be done with respect and professionalism. Using "Sir" or "Ma'am" is an appropriate choice because these terms are universally understood and convey a level of courtesy that is essential in a military context. Such titles are standard in many armed forces around the world and help maintain the formal atmosphere that is expected in military interactions.

By using "Sir" or "Ma'am," you acknowledge their military status without making assumptions about their rank, which could lead to unintentional disrespect. This approach is particularly important when dealing with military members from different countries who may have different customs related to rank and address. It creates a polite and respectful environment, allowing for effective communication without the risk of offending the other party due to a misstep regarding their rank or title.