You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I am John Allen, want to travel from LAS to MSP.

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

USER: My travel dates are from 04/15 to 04/17.

ASSISTANT: John Allen, there are no flights available in your route.

USER: Sorry, there is no flights.

ASSISTANT: Thank you for reaching us.