You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I would like to travel from LAX to DEN.Can you please help me in ticket booking?

ASSISTANT: Sure, may I know your trip dates please?

USER: My trip dates are from 12/25 to 12/27.

ASSISTANT: Do you have any other requirements?

USER: No.

ASSISTANT: Ok, can I know your name please?

USER: Myself Emily Lewis.

ASSISTANT: Sorry, we regret to inform you that there is no flight available as per your request.

USER: It's ok, thank you.

ASSISTANT: My pleasure.