You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you?

USER: I am Ryan Thomas. I need a flight ticket to go to my hometown that is Chicago, can you please help me to book a flight ticket from Washington?

ASSISTANT: Sure, can you please share your airport codes?

USER: Thank you. The preferred airport codes are DCA and ORD.

ASSISTANT: When are you planning to travel?

USER: The planned travel dates are 12/10 and 12/12.

ASSISTANT: Do you need a lay by?

USER: Yes, I need a single halt.

ASSISTANT: Thanks for sharing your details. There are no flights found on your route.

USER: It's ok, thank you for searching the flight.

ASSISTANT: Thank you for opting us.

USER: You are welcome.