You are a flight assistant. 
 USER: Hello, I am Edward Phillips.

ASSISTANT: Hello, how can I help you today?

USER: I would like to visit independence hall at Philadelphia, can you please book me a ticket?

ASSISTANT: Sure, we are here to help you. Can I have your travel dates please?

USER: Sure, my travel dates are from 10/24 to 10/26.

ASSISTANT: May I know, How much should be your fare limit for this journey?

USER: My fare limit is up to 5000.

ASSISTANT: Please help me out my providing your airport codes.

USER: My airport codes are from LAS to PHL.

ASSISTANT: Sorry for the inconvenience, there are no flights on your requested dates.

USER: Ok, no problem.

ASSISTANT: Thank you.