You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. Can you please tell me how may I help you?

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

ASSISTANT: Sure, I will definitely help you to reserve the plane ticket. Can you please tell me your preferable trip dates?

USER: I prefer to travel on Nov 18 and Nov 20.

ASSISTANT: Ok, please tell me your requirement about the number of connections in between your journey.

USER: I need a direct flight.

ASSISTANT: May I know your name please?

USER: I am Brandon Lopez.

ASSISTANT: I am really sorry to inform you that, there are no flights running in this route due to some climatic effects.

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

ASSISTANT: You are welcome. Thank you for opting us.