You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I am planning to return on 01/21 from Washington after finishing of my work. Can you help me book a flight ticket from Chicago on 01/19?

ASSISTANT: Sure, can I know your airport codes?

USER: I would like to reach IAD from ORD.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: 1009 flight is available in Spirit airline. Airfare is 200.

USER: You can proceed for booking.

ASSISTANT: Ok, your booking has been made.

USER: Thank you for your service.

ASSISTANT: Thanks for choosing our agency. May I know your name for documentation purpose?

USER: Sure, my name is Angela Lewis.

ASSISTANT: Thank you.