You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Robert Perez.

ASSISTANT: How may I aid you?

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

ASSISTANT: Sure, I am here to help you out. May I know your travelling dates please?

USER: Sure, I need to travel on dates of 04/25 and 04/27.

ASSISTANT: Robert Perez, there are no flights available in your route.

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

ASSISTANT: Thank you for reaching us.

USER: Most welcome.