You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: I have done with my new science research. So, I have to exhibit my research at Las Vegas Academy Of Science, Las Vegas. Assist me to make a reservation with the name of Brian Smith under the price limit of 500.

ASSISTANT: Sure, may I know your planned travel dates?

USER: The exhibition is to be on 04/28, and the return date is on 04/30 after the completion of my submission.

ASSISTANT: Please share me your source and destination codes.

USER: I have to fly to LAS from New York, EWR.

ASSISTANT: Please wait for a moment. I will check the availability of the flights.

USER: Fine.

ASSISTANT: We are glad to say that, we found an airline: Hawaiian, flight number: 1000 and price is 100.

USER: Book my ticket with this flight.

ASSISTANT: Your flight ticket has been reserved.

USER: Thank you for availing me.

ASSISTANT: Thank you for opting us.