You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: This is David Walker. Basically, I am a movie lover I want to visit Fox Theatre in Detroit. Can you please help me to book a flight ticket?

ASSISTANT: Sure, can you please mention your journey dates?

USER: Sure, my travel dates are from 10/14 to 10/16.

ASSISTANT: Please specify your airport locations?

USER: My source airport code is PA -PHL and my destination airport code is MI - DTW.

ASSISTANT: Do you have any specifications to be met?

USER: Yes, I need a break in my journey and fare limit should not cross 500.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Thank you for your valuable time, unfortunately no flights available on that route.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for opting us.