It's not part of the actual articles in the game, it's merely by creating a bill, for example
Bill title: National Name Reform
Bill description:
Article I - The name of the nation shall change from "Le Royaume Yeudi de Beiteinu [The Yeudish Kingdom of Beiteynu]" to the "State of Beitenynu".
and you can then put that to vote. It needs to pass with a 2/3 majority of the players (I believe thats the rule now). and once thats been done/passed successfully you post it in this thread:
viewtopic.php?f=11&t=4361 and the moderators will get to it and change it.
Hope thats what youre looking for.
Enjoy,
Farsun.