My name is Mark and I would like to reserve a flight.
Can I have your flight ID, please?
My lucky flight number is 26 if you must have it.
Sorry, but the flight with id '26' is not available any more.
I said the flight number is 783. 
Sorry, but the flight with id '783' is not available any more.
great, I guess I won't get a flight then. thats all I'll be needing today then.
Flight 26 is available.  Should I reserve it for you?
no, I don't want any flights. That's all I need.
I'm sorry, but your reservation request was unsuccessful.