@Paul ******
The Myanmar passport has only one field for "Name", whatever name the person has, it's written there in a single line. So if somebody's name is, Aye Chan Phyu (for example), that person could argue any of them are their "last name", if needed, but the passport doesn't specify. I don't know if they have changed it recently, like 1 or 2 years ago? But all "old" passports that haven't expired remain still valid and legal.