You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I planned to meet my cousin in SFO, can you please help me to book a flight ticket from DCA?

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

USER: I prefer to travel on Feb 1 and Feb 3.

ASSISTANT: Do you have any other requirements?

USER: I prefer to travel in a economy class.

ASSISTANT: Can I know your name please?

USER: I am Kenneth Lopez. I need a connecting flight to travel.

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

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Most welcome.