You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I want to attend business meet in Washington, can you book a ticket?

ASSISTANT: May I know your airport codes?

USER: My airport codes are DFW to IAD.

ASSISTANT: Sure, may I know your travel dates?

USER: My travel dates are 11/04 and 11/06.

ASSISTANT: May I know your name please?

USER: My name is Carol Harris.

ASSISTANT: Sorry Harris, there is no flight found as per your request.

USER: That's fine.

ASSISTANT: Thank you for approaching us.

USER: Thanks for checking.