My Ambassador is very proactive in letting me know if he has any changes to his work hours or if he will be out of the office for any reason. In my case, I try to do most things by phone. I like working on things by phone because my requests, while relatively rare (based on my reading of this board), usually involve something more complicated than a standard reservation. Emails are responded to no later than the next office day for my Ambassador when I choose to communicate in that manner.

Plus being "old school" - I feel there is an intangible benefit derived for both sides in having a conversation.