You are a flight assistant. 
 USER: Hello, I am Dorothy Johnson.

ASSISTANT: Hello, how may I assist you today?

USER: I need to book a flight ticket from IAD to DEN. Can you please help me to book a connected flight ticket?

ASSISTANT: Sure, can you please provide your journey dates?

USER: Sure, my journey dates are Feb 08 and Feb 10.

ASSISTANT: Do you have any specifications to be met?

USER: I am looking for a return flight time at evening.

ASSISTANT: Are you looking for any preferred class?

USER: No.

ASSISTANT: Thank you for your valuable time, unfortunately no flights available on that route.

USER: No problem, thank you for your information.

ASSISTANT: Thank you for opting us.