You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I aid you?

USER: Joseph Scott here. I heard there is a good tourist attractions in Las Vegas. So book a ticket from TX - HOU to NV - LAS.

ASSISTANT: Sure. May I know your journey dates?

USER: My preferred journey dates are 03/19 to 03/21.

ASSISTANT: Do you have any preferences?

USER: My budget is up to 1000.

ASSISTANT: Thanks for your details. There are no flights available to your destination.

USER: That's Ok, thanks for your response.

ASSISTANT: Thank you.