You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I serve you?

USER: I am planning to book a ticket from PHX to DFW. Can you please help me out?

ASSISTANT: Sure, may I know your travelling dates?

USER: I am planning to travel on Mar 20 and return back on Mar 22.

ASSISTANT: Do you have any connection limit?

USER: I am looking for a connecting flight.

ASSISTANT: Any other preferences?

USER: I am looking for a Business class.

ASSISTANT: May I know your name?

USER: My name is Paul Lopez.

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

USER: That's fine, thank you for your service.

ASSISTANT: Thank you.