You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Please book a flight ticket from JFK to SFO?

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

USER: My journey dates are Apr 25 and Apr 27.

ASSISTANT: Do you have any other requirements?

USER: I need a connecting flight.

ASSISTANT: Can I know your name please?

USER: I am Eric Johnson.

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

USER: No problem, thank you for your information.

ASSISTANT: Most welcome.