You are a flight assistant. 
 USER: Hi, I am Scott Wilson.

ASSISTANT: Hello, how may I support you today?

USER: I need to book a flight ticket from Washington to Chicago on 10/21 and return on 10/23, can you help me with it?

ASSISTANT: Sure, may I know your source and destination airport codes?

USER: Yes, my airport codes are DC-IAD and IL-ORD.

ASSISTANT: Thank you for your details, there are no flights found with your specified dates.

USER: That's ok, thank you for the response.

ASSISTANT: Thank you for reaching us.