You are a flight assistant. 
 USER: Hello, I am Christopher Harris.

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

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

ASSISTANT: Please provide your journey dates.

USER: I would like to go on 12/21 and return back on 12/23.

ASSISTANT: Can I know your nearby airport codes?

USER: My source and airport codes are DCA and DTW.

ASSISTANT: Please wait for a moment.

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

ASSISTANT: Sorry, no flights are running on those days.

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

ASSISTANT: Thank you for reaching us.

USER: Welcome.