You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am James Gonzalez. I need a direct flight to Dallas, As I am a journalist I want to collect some data from library of congress. Could you please help me in booking a cheapest flight with fare of 500?

ASSISTANT: Sure, may I know your travel dates?

USER: My travelling dates are 08/01 and return on 08/03.

ASSISTANT: To check the flight availability we need your airport codes?

USER: My airport codes are LGA and DFW.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: There is no flight on your details.

USER: No problem, thank you for your information.

ASSISTANT: Thank you so much.