I'm really sorry Madam, I missed your lecture because I was ill yesterday.
I'm not upset that you couldn't keep the appointment, but you didn't call me when someone doesn't turn up and doesn't call it makes someone else wait.
You're right, I apologize. I didn't feel well and I guess I just wasn't thinking of calling you at the time.
OK apology accepted. Now, I suppose you need to set up another appointment.
Yes, I do. But I'm really worried about my project. Can you see me now if I wait?
No, but I can see you at 3:00 o'clock this afternoon or during my office hours on Tuesday, Thursday or Friday.
Great. Your office hours are best at 2:00 o'clock Tuesday. OK?
OK, be there in time by then.