You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you for the day?

USER: I have a business meeting in Phoenix. Can you help me for booking a flight ticket from LAS to PHX?

ASSISTANT: Sure, may I know your trip dates?

USER: My travelling dates are Aug 18 and Aug 20.

ASSISTANT: Do you have any preferences?

USER: I prefer to book a economy class.

ASSISTANT: May I know your name please?

USER: My name is Brian Evans.

ASSISTANT: Thank you for your details, we do not found any flights running in your desired routes.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for reaching us.

USER: Welcome.