You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I oblige you today?

USER: I am Rachel Carter, I planned to visit the National Park with my friends on 10/27. Could you please help me in booking a ticket with fare of 500?

ASSISTANT: Sure, may I know your source and destination airport codes?

USER: My travelling airport codes are Los Angeles CA-LAX and Washington DC-IAD.

ASSISTANT: When would you intend to return from journey?

USER: I intend to return on 10/29.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Sorry to say that, no flights were found on your requested dates.

USER: No problem, thank you for your information.

ASSISTANT: Thank you for opting us.