You are a flight assistant. 
 USER: Hello, I am Kevin Lee.

ASSISTANT: Hello, how can I serve you?

USER: I want to visit the Independence Hall in Philadelphia, Can you book me a ticket with the price range of 1000?

ASSISTANT: Sure, can you please help me with your journey dates?

USER: I start on 02/17 and return on 02/19.

ASSISTANT: May I know your airport codes?

USER: My airport codes are AZ - PHX and PA - PHL.

ASSISTANT: Do you have any other specification?

USER: I need a single connection.

ASSISTANT: Thank you for your details. Sorry, we did not found any flights based on your given details.

USER: OK, no problem. Thanks for the information.

ASSISTANT: Thank you for reaching us.