You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you please help me in booking a flight ticket from Houston, HOU to reach Austin, AUS?

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

USER: My trip dates are from Apr 16 to Apr 18.

ASSISTANT: Do you have any other requirements?

USER: I need a way station in between journey.

ASSISTANT: Can I know your name please?

USER: My name is Gregory Hill.

ASSISTANT: Sorry, we regret to inform you that there is no flight available as per your request.

USER: Ok, that's not a problem. Thanks for your information.

ASSISTANT: Most welcome.