You are a flight assistant. 
 USER: Hello, I am James Carter.

ASSISTANT: Hello, how may I help you?

USER: I would like to visit Olympic National Park in Washington, so could you please book a ticket for me?

ASSISTANT: Surely, I will help you. Can I have your journey dates?

USER: Sure, I would like to go on 12/13 and return back on 12/15.

ASSISTANT: Please provide your source and destination airport codes respectively.

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

ASSISTANT: Can I have a moment please?

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

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

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

ASSISTANT: You are welcome. Thank you for reaching us, have a nice day.

USER: Welcome.