You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: Can you help me to book a business class flight ticket?

ASSISTANT: Sure, may I know your source and destination airport codes?

USER: My airport codes are PHL and LAS.

ASSISTANT: Let me know your travelling dates.

USER: My travel dates are Apr 26 and Apr 28.

ASSISTANT: May I know your connection limit?

USER: I prefer connecting flight for this trip.

ASSISTANT: Do you have any other requirements?

USER: I would like to return back in the evening time.

ASSISTANT: May I know your name please?

USER: My name is Catherine Perez.

ASSISTANT: Sorry, there are no flights found with your given details.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for opting us.