Fair Winds and Following Seas - S10-E22
Continuity mistake: The opening scene, which is a replay of the ending scene from the previous episode, is slightly different. When Gen. Cresswell tells Mac she'll be stationed in San Diego, Harm comments "It's only a five hour plane ride" instead of "it's only five hours away", and when Rabb is promoted to Captain, Cresswell briefly pauses at "it's" when he says "By the way, it's a captain's billet", while there was previously no pause.
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.