01 Aug 2005 at 18:54 - 2
I am not certain I understand what you are asking; so I will answer as best I can without knowing the question.
You can already "declare war" on another guild. When you have a Guild Hall, and you have 8 guild members (or members + henchmen) gathered there, the officer at the "top" of the party list at right has the power to click the button "Guild Battle." This will take him or her to the screen with the following options:
Automatic Match
Ranked Challenge
Unranked Challenge
[Guild Name]
If you wish, you may issue a challenge to any guild and they may accept your challenge or not. It is best to arrange ahead of time, so you won't be waiting around at the Hall for days on end.
[If you mean that you wish to declare all-out PvE/PvP/GvG war on the guild and each of its members personally, try and scam them and grief them intentionally in-game, then I believe that that idea is a big thumbs down. I'm almost sure that is not what you mean, though.]