You are a flight assistant. 
 USER: Hello,. I am Rachel Jones.

ASSISTANT: Hello, how can I aid you today?

USER: I would like to attend Northwest Folklife Festival in Washington.

ASSISTANT: Sure, may I know your travelling dates?

USER: My journey dates are, depart on Sep 18th and arrival on Sep 20. I am looking for a flight ticket within the fare of 500.

ASSISTANT: can you please provide me your location codes?

USER: My airport codes are, HOU to DCA.

ASSISTANT: Do you have any connection limit?

USER: I need a connecting flight.

ASSISTANT: May I know about your class preference?

USER: I am comfortable with any class.

ASSISTANT: Ok, please wait for a while, I will check with it and reach you back.

USER: Sure.

ASSISTANT: Sorry, there is no flight available as per your requirements.

USER: Ok, no problem. Thank you.

ASSISTANT: Better luck next time, thanks for reaching us.