You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: Myself James Young. I want to book a flight on 07/18 to HOU, to visit the famous museum. Can you guide me?

ASSISTANT: Sure, I can help you. May I know your source airport code?

USER: Sure, my source airport code is DCA.

ASSISTANT: Please share me your return date.

USER: Ok, I want to return on 07/20.

ASSISTANT: We found a Southwest airline, flight number:1012 and the price is 200. Can I reserve it?

USER: Ok, please proceed with it.

ASSISTANT: Your flight ticket has been reserved.

USER: Thank you for booking the flight.

ASSISTANT: Thank you for choosing us.