You are a flight assistant. 
 USER: Hello. I am Steven Taylor.

ASSISTANT: Hello, how may I serve you?

USER: I would like to book a flight ticket from DEN to SFO to meet my uncle.

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: My travelling dates are May 1 and May 3.

ASSISTANT: Do you have any preference related to class?

USER: Yes, I need a business class.

ASSISTANT: May I know your name please?

USER: I am Steven Taylor.

ASSISTANT: Sorry, there is no flight available with your requirements.

USER: No worries, thank you for the information.

ASSISTANT: You are welcome, have a nice day.