You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you today?

USER: I have to meet my casino business partner in Las Vegas. Please book my ticket from DEN to LAS.

ASSISTANT: Sure, I will help you with that. Can you please share your journey dates?

USER: My travel dates are 04/12 and 04/14.

ASSISTANT: may I know your name please?

USER: My name is Nicole Evans.

ASSISTANT: Wait for a minute.

USER: Sure.

ASSISTANT: I am sorry to say that there is no flight found.

USER: It's ok, thank you for the information.

ASSISTANT: Thank you.