You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: Please book a flight ticket from DFW to LAX?

ASSISTANT: Sure, may I know your trip dates?

USER: My journey dates are Aug 21 and Aug 23.

ASSISTANT: Do you have any class preference?

USER: No.

ASSISTANT: Let me know your connection limit?

USER: I need a connecting flight.

ASSISTANT: Any other requirements to be met?

USER: I prefer a return flight time at evening.

ASSISTANT: May I know your name?

USER: I am Rachel Robinson.

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

USER: No problem, thank you for your information.

ASSISTANT: Thank you for reaching us.