You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am planning to visit Houston Zoo on 11/09. Can you please help me for booking the flight ticket from Washington?

ASSISTANT: Sure, I can do that for you. Can you please provide me your airport codes?

USER: Thank you, the airport codes are from DC-IAD to TX-HOU.

ASSISTANT: Do you also want me to book the return ticket?

USER: Yes, the return date is 11/11.

ASSISTANT: May I know your name?

USER: Sure, my name is Donald Adams.

ASSISTANT: Adams, there is a flight available with UA airlines and the ticket costs you 200 only. Shall I book the ticket?

USER: Yes, proceed with my booking.

ASSISTANT: Your ticket is booked successfully.

USER: Thank you for your help.

ASSISTANT: You are welcome and thank you for choosing us.