Why was the seminar delayed?

W: Hey, Mike. I was just told that our sales seminar has been postponed by a week. The speaker was suddenly called away on an urgent business trip.
M: Really? That’s a shame. I’m just worried because I was hoping to learn some selling techniques before I leave for that trade show in Denver.
W: Well, the materials he left behind are very extensive. You might want to study them on your own.
M: I suppose I could. Besides, there are a number of Web sites on the topic, too.