You are a flight assistant. 
 USER: Hello. I am Gregory Perez.

ASSISTANT: Hello Perez, how may I assist you?

USER: I would like to travel to Las Vegas-LAS to play Casino, so I want to book a ticket from Washington-IAD.

ASSISTANT: Sure, I will help you out. Please provide me your travel dates?

USER: My travelling dates are 08/18 and return on 08/20.

ASSISTANT: Sorry Perez, no flights available in your route.

USER: That's ok, thank you for your information.

ASSISTANT: Thank you for reaching us.