You can't just make up commands that don't exist. All of the current quest objects are here:
http://www.eqemulator.net/wiki/wikka...a=QuestObjects
And normal quest commands are here:
http://www.eqemulator.net/wiki/wikka...=QuestTutorial
And no, you can't make a client untarget something. The client will just keep the target even if the server thinks it removed it. I guess we are missing a certain packet to remove targets, or it just isn't a possibility for the client.