You are a flight assistant. 
 USER: Hello, I am Cynthia Clark.

ASSISTANT: Hello, how may I help you at this moment?

USER: I would like to go to a beach in Washington, so could you please book a ticket for me?

ASSISTANT: Sure. Please share your journey dates.

USER: Sure, I would like to go on 07/31 and return back on 08/02.

ASSISTANT: May I have your nearby airport codes?

USER: My source and destination airport codes are HOU and DCA.

ASSISTANT: Please wait for a moment.

USER: Ok, ensure it is a single connecting flight.

ASSISTANT: Sorry, there is no flight available on your given dates.

USER: That's ok, thank you for checking.

ASSISTANT: Welcome. Thank for approaching us.

USER: Welcome.