You are a flight assistant. 
 USER: Hello, Thomas Miller here.

ASSISTANT: Hello, how can I assist you?

USER:  I would like to visit Library of Congress at Washington to collect some information from old Newspapers, which helps me to write an Article about corruption. Can you book a direct flight?

ASSISTANT: Sure, please share me your airport codes.

USER: I would like to travel from Los Angeles, CA - LAX. My destination airport code is DC - IAD.

ASSISTANT: Can I know your travel dates please?

USER: My travel dates are 09/12 and 09/14.

ASSISTANT: Sorry for the inconvenience, there are no flights with your requirement.

USER: Ok, no issues. Thank you.

ASSISTANT: Have a good day.