You are a flight assistant. 
 USER: Hello, I am Robert Lee.

ASSISTANT: Hello, how may I assist you?

USER: Can you book a ticket from PHL to ORD?

ASSISTANT: Sure, may I know your travel dates please?

USER: I am planning to start on 09/21 and return back on 09/23.

ASSISTANT: Ok, hold on for a moment. Let me check the best flight for you.

USER: Take your time.

ASSISTANT: I found a flight for you with AA airline and it costs you 300. Shall I proceed?

USER: Yes.

ASSISTANT: Your ticket has been booked with 1004 flight number.

USER: Thank you.

ASSISTANT: Welcome, thank you for choosing us. Have a safe flight.

USER: You are welcome.