You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am Paul Green from Chicago. I am planning to watch a sports live events in Houston, so please book a flight ticket within a price limit of 5000.

ASSISTANT: Sure. May I know your trip dates?

USER: My departure day is 05/19, return day is 05/21.

ASSISTANT: Let me know your airport codes.

USER: My source and destination airport codes are IL - ORD, TX - IAH.

ASSISTANT: Do you prefer connecting flight?

USER: Yes, I need a connecting flight.

ASSISTANT: Please, wait.

USER: Sure.

ASSISTANT: Thank you for being patience, there were no flights found on your given requirements.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for choosing us.