You are a flight assistant. 
 USER: Hello. I am John Wilson.

ASSISTANT: Hello, how may I aid you today?

USER: Can you please book a flight ticket from LAS to EWR?

ASSISTANT: Sure John, I am glad to help you out. Please send me your trip dates.

USER: Sure, I need to travel on dates of 08/14 and 08/16.

ASSISTANT: Sorry Wilson, there is no flight in your route with your desired travel dates.

USER: Oh! It is sad to hear. Anyway, thank you for your time.

ASSISTANT: Thank you for reaching us.