How to call a person holding advance diploma?

There's no single universally accepted title for someone holding an advanced diploma. The best way to address them depends on context and your relationship with them. Here are some options:

* Mr./Ms./Mx. [Last Name]: This is always a safe and respectful option, regardless of the specific field or their age.

* [First Name]: If you have a casual relationship with them.

* [Title] [Last Name]: If the advanced diploma is in a specific field, they may have a professional title associated with it (e.g., "Technician," "Analyst," "Designer"). Use this title if appropriate and known.

Avoid:

* Assuming a title like "Doctor" or "Professor" unless their advanced diploma explicitly grants that title. Advanced diplomas are not equivalent to a doctorate or professorship.

In short, err on the side of formality unless you know it's appropriate to be more casual. If unsure, Mr./Ms./Mx. [Last Name] is always a good choice.