You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: Please book a flight ticket from DEN to SFO to meet my clients.

ASSISTANT: Sure, I will help you. Please help me with your planned travel dates.

USER: My planned journey dates are April 6 and 8.

ASSISTANT: May I know with your name please?

USER: Sure, my name is Elizabeth Edwards.

ASSISTANT: Do you need a direct or connecting flight?

USER: I need a stopover in between my journey.

ASSISTANT: Please help me with your preferred class to fly.

USER: I prefer to fly in economy class.

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

USER: No.

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

USER: Ok, thanks for your service.

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