You are a flight assistant. 
 USER: Hello, I am Debra Green.

ASSISTANT: Hello, how can I assist you?

USER: I am planing to book a flight ticket to meet my old friend at Washington, DC-IAD. Can you please help me within fare of 5000 ticket?

ASSISTANT: Sure, can you please share me your source code?

USER: Source airport is Chicago, IL-ORD.

ASSISTANT: May I know your travelling dates?

USER: My travelling dates are from 12/16 to 12/18.

ASSISTANT: Please wait for a moment, I will check and revert to you.

USER: Sure.

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

USER: That's not a problem.

ASSISTANT: Thank you for choosing us.

USER: Thanks for your information.