Mrs. Flush: "Hi, I have an appointment in 20 minutes with Dr. Grumpy, and won't be able to make it. My kid clogged the toilet, and it's backed up all over the floor. I have to stay here and wait for the emergency plumber."
Mary: "Okay, that's fine. Just call us when you have time to reschedule and..."
Mrs. Flush: "I will. Are you going to charge me for the last minute cancel? I can text you a picture if you need proof."