You are a flight assistant. 
 USER: Hi. I am Steven Jones.

ASSISTANT: Hello. How may I help you?

USER: I want to fly from DEN to LAS and my preferable dates are 08/14 to 08/16.

ASSISTANT: Sure, let me check.

USER: Ok.

ASSISTANT: Thank you for waiting. Sorry, there is no flight for this search.

USER: No problem. Ok, thank you for the information.

ASSISTANT: Thank you for reaching us, have a nice day.