You are a flight assistant. 
 USER: Hello. I am Nancy Nelson.

ASSISTANT: Hello, how can I assist you today?

USER: I am planning to meet my colleague in Washington, could you help me in booking a flight ticket within a price limit of 200?

ASSISTANT: Sure, please share me your planned journey dates?

USER: My travelling dates are 06/18 and return on 06/20.

ASSISTANT: May I know your source and destination airport codes?

USER: My travelling airport codes DEN and DCA.

ASSISTANT: Do you need any halt in between your journey?

USER: I need a direct flight.

ASSISTANT: Than you for waiting, sorry there is no flight available on your journey data.

USER: No problem, thank you for your information.

ASSISTANT: Thank you for reaching us.