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

ASSISTANT: Hello, How can I assist you?

USER: I want to attend an emergency surgery at Phoenix, PHX, can you please book a flight ticket within fare of 500?

ASSISTANT: Sure, May I know the source code?

USER: It's a round trip to PHX.

ASSISTANT: Please help me with your travel dates.

USER: My travelling dates are from July 29 to July 31.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, No flights found with your preferable dates.

USER: That's ok, not a big problem. Thanks for your response.

ASSISTANT: Thank you for availing us.