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

ASSISTANT: Hello, how may I help you at this moment? Nice. Can I have your journey dates?

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

ASSISTANT: Ok.

USER: I would like to go on 12/25 and return back on 12/27.

ASSISTANT: Please share your nearby airport codes.

USER: My source and destination airport codes are SEA and IAD.

ASSISTANT: Please wait for a moment.

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

ASSISTANT: There is a connecting flight available with UA airlines, shall I proceed?

USER: Ok, please proceed for further.

ASSISTANT: Your booking is done with flight number 1005. Happy journey.

USER: Thank you.

ASSISTANT: You are welcome. Thank you for reaching us.

USER: Welcome.