You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello. How can I assist you today?

USER: I want to book a flight ticket within my price limit 500. Will you help me in flight booking?

ASSISTANT: Sure, may I know your journey dates?

USER: My travelling dates from 07/31 to 08/02. I want a direct flight.

ASSISTANT: Can you please provide me your source and destination airport codes?

USER: I am attending for seminar in Rice University Campus, TX - HOU and my origin from NV - LAS.

ASSISTANT: May I know your name please?

USER: My name is Donald Jackson.

ASSISTANT: Ok. Sorry to say that, there is no flights found with your given details.

USER: Not an issue. Thank you, for your quick response.

ASSISTANT: Ok, thank you for choosing us.