You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: Can you aid me in booking a flight ticket from LAS to DEN?

ASSISTANT: Sure, may I know your planned travel dates?

USER: I am planning to start on Mar 27th and return back on Mar 29th.

ASSISTANT: Do you have any specifications?

USER: I prefer to travel in business class.

ASSISTANT: Please provide me the name.

USER: Myself Patricia Johnson.

ASSISTANT: Sorry, there are no flights are available for your desired intent.

USER: No issues. Thank you for checking.

ASSISTANT: Thank you for reaching us.