You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Reserve a flight ticket from AUS to LAS.

ASSISTANT: How can I been at your service? Ok, may I know your journey dates?

USER: My travel dates are from 08/17 to 08/19.

ASSISTANT: May I know on whose name I have to book?

USER: Benjamin Nelson here.

ASSISTANT: Nelson, I regret to inform your that there is no flight available at those locations.

USER: Not a problem. Thank you.

ASSISTANT: Thank you for choosing our service.