Dr. Donald Mallard: You sure you won't have dinner with me tonight, Viv?
Special Agent Vivian Blackadder: Oh, Ducky, you're disgusting!
Dr. Donald Mallard: The pursuit of sex is an affirmation of life, Vivian. That's why older men are so lascivious.
Special Agent Vivian Blackadder: I'm talking about your lack of respect for the dead.
Dr. Donald Mallard: I have the utmost respect for the dead.
Special Agent Vivian Blackadder: Well, that's obvious from the way you speak to them.
Dr. Donald Mallard: If you were dead, wouldn't it be nice if you were spoken to, rather than about?
Vivian Blackadder: Amad bin Atwa supplied money and explosives to Hasan Mohammed, who executed the attack on the Cole. They're an all-Jihad team that's been together for nine years. If Bin Atwa gives up Hasan, I want in on the kill.
Gibbs: We're not tasked with capturing Hasan Mohammed.
Vivian Blackadder: Gibbs, my brother died on the Cole.
Gibbs: I know that.
Vivian Blackadder: Then get me in on this!
Gibbs: You're not here to use NCIS as your personal instrument of revenge. You get your head around this murder case, or you pull your tailored suit out of mothballs and you march your butt right back to the J. Edgar Hoover Building.
Answer: Officially, the individual has been ordered to attend, failing to could be interpreted as either, Failure to follow orders, dereliction of duty, going AWOL, or even desertion. It would depend on the underlying reason as to why the person doesn't appear.