You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I am Kevin Williams. I want to visit national gallery of art at Washington, DC - IAD. Can you please help me with book a direct flight?

ASSISTANT: Sure, may I know your planned travel dates?

USER: I have planned my travel dates are 01/29 to 01/31.

ASSISTANT: May I know your source point?

USER: My source point is from Minneapolis & St. Paul, MN - MSP.

ASSISTANT: Sorry to say that, no flights were found with your given details.

USER: OK, no problem.

ASSISTANT: Thank you for opting us.

USER: Thanks for your information.