Leigh - Really appreciate this post.  Especially, like the planning and preparation points that you suggested. After being specific and discussing the impact, I also like the idea of asking the person, what they might be able to do to remedy the situation or ensure it does not happen again.  It makes them take some ownership.  Also, as soon as they start to talk about how to correct, then you've got there buy-in that there was an issue in the first place.  All great points!