You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Gary Hall here.

ASSISTANT: How may I assist you at this moment?

USER: I want to enjoy my holiday at Las Vegas, could you book my ticket from Dallas?

ASSISTANT: Sure, I am glad to help you with that. Can you please provide your planned dates of travelling?

USER: My itinerary dates are 11/09 and 11/11.

ASSISTANT: Ok, may I know your origin and destination airport codes for booking?

USER: My genesis and terminus airport codes are DFW and LAS.

ASSISTANT: Please wait a moment to check the flights in your route.

USER: Sure.

ASSISTANT: We regret to inform you that there are no flights moving to your region with your planned dates of travelling.

USER: No problem, thank you.

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