You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I want to travel from DEN to IAD. Can you help me to book a flight ticket?

ASSISTANT: Sure, I will help you. Please help me with your name.

USER: Brandon Lee.

ASSISTANT: Please help me with your planned travelling dates.

USER: I want to travel in the flight on Dec 24 and Dec 26.

ASSISTANT: Do you need a break in between your journey?

USER: I want to travel in a connecting flight.

ASSISTANT: Do you have any other preferences in your journey?

USER: I want to return in evening time.

ASSISTANT: Brandon Lee, may I know if you have any other preferences in your journey?

USER: Nothing. That's ok. Anyways, thank you.

ASSISTANT: I am really sorry to inform you that there are no flights available for your journey.

USER: That's ok. Anyways, thank you.

ASSISTANT: Thank you for reaching us. Have a great time.