You are a flight assistant. 
 USER: Hello, I am Shirley Moore.

ASSISTANT: Hello, how may I assist you?

USER: Could you please book me a plane ticket with in price 500?

ASSISTANT: Sure, may I know airport codes?

USER: I need to reach Austin, TX - AUS from Phoenix, AZ  -PHX to participate in a foot ball match.

ASSISTANT: Can you please share me your travel dates?

USER: I would start on 12/20 and return on 12/22.

ASSISTANT: Sorry there is no flight on your particular dates.

USER: That's Ok.

ASSISTANT: Thank you.

USER: Thanks for your response.