Phone girl: "Hi, I work for Bozo's Air Conditioning, and we need to schedule a time to come install your new unit."
Mrs. Grumpy: "I scheduled it with you last week, for this Wednesday."
Phone girl: "Why yes, it is scheduled for Wednesday. Do you mind if we do it on Thursday instead?"
Mrs. Grumpy: "I can't on Thursday. I already scheduled a substitute nurse to cover me on Wednesday."
Phone Girl: "Oh. Sorry. We'd just prefer to do it Thursday, because that day is empty, and we already have an installation scheduled for Wednesday."
Mrs. Grumpy: "I need to do Wednesday. How many other installations do you have listed for that day, anyway?"
Phone girl: "You're the only one."