You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: Kevin Phillips here. Please help me out in booking the ticket from DCA to ORD.

ASSISTANT: Sure, can you share your journey dates?

USER: My trip dates will be Dec 23 to Dec 25.

ASSISTANT: Do you have any preferences?

USER: Return time must be in the evening. I want direct flight.

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

USER: That's ok, thank you.

ASSISTANT: Thank you for reaching us.