You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am planning to travel from SFO to DEN. Can you please help me to book a ticket?

ASSISTANT: Sure, can you please let me know your travel dates?

USER: I want to start on Nov 6 and return on Nov 8.

ASSISTANT: Ok, do you have any preferences?

USER: I would prefer business class.

ASSISTANT: May I know your name?

USER: Deborah Hill here.

ASSISTANT: Ok, is there any other preferences?

USER: No.

ASSISTANT: Deborah Hill, I am very sorry to tell you. There is no flight available as per your requirements.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: You are welcome and have a nice day.