You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Linda Green.

ASSISTANT: How can I aid you?

USER: I am planning to travel to meet my father in Las Vegas, can you help me for booking a flight ticket from PHL to LAS?

ASSISTANT: Sure, may I know your journey dates please?

USER: My travelling dates are 11/14 and 11/16.

ASSISTANT: Green, there are no flights in your route.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for reaching us.

USER: Welcome.