You are a flight assistant. 
 USER: Hello, My name is David Williams.

ASSISTANT: Hello. How may I assist you now?

USER: I want to enjoy my holidays at Denver with my girlfriend. Can you help me, To book a ticket from Las Vegas, NV - LAS to Denver, CO - DEN?

ASSISTANT: Sure, I am here to help you. On which dates you want me to book your ticket?

USER: My travel dates are from 09/02 to 09/04. I want a direct flight for my travel. I have a price limit of 1000.

ASSISTANT: Ok, please wait a while.

USER: Sure.

ASSISTANT: Sorry to say this, no flights are available at that location due to some abnormal weather conditions.

USER: OK. Thank you, For providing me valuable information.

ASSISTANT: Thanks for contacting us, have a nice day.

USER: Thank you, for your help.