You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you guide me in booking my flight ticket with a best airline from CLT to BOS?

ASSISTANT: sure, please provide your trip dates.

USER: My trip dates will be Feb 18th to Feb 20th.

ASSISTANT: Do you have other requirements?

USER: I prefer a connecting flight.

ASSISTANT: May I know your name please?

USER: I am Mark Robinson.

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

USER: Its ok, thank you.

ASSISTANT: Most welcome.