answer: #Person1# helps #Person2# book an economy-class round ticket to Shanghai.
documents: #Person1#: Good morning, Northwind Airways. May I help you?
  #Person2#: Yes, do you have any afternoon flights to Shanghai on July seventh?
  #Person1#: One moment please. Yes, there is a flight at 12:45 PM and one at 4:40 PM.
  #Person2#: Either of those would be fine. Can you tell me how much a return flight would cost? I'll be returning on July twenty-first.
  #Person1#: Economy, business, or first class?
  #Person2#: Economy, please.
  #Person1#: OK, that will be $500. Which afternoon flight would you like to take on July seventh?
  #Person2#: The 441.