You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I guide you?

USER: I am Ronald Perez. I would like to book a flight ticket from DCA to BOS.

ASSISTANT: On which dates you are willing to travel?

USER: I am planning to start my trip on 12/21 and fly back on 12/23.

ASSISTANT: Ok, please give me a minute.

USER: Please take your time.

ASSISTANT: For these location, I got a direct flight for you. Shall I proceed?

USER: No, I want a flight with single connection. Can you please help me with that?

ASSISTANT: There is a no flight with single connection.

USER: It is ok. Anyways, thank you for the information.

ASSISTANT: You are welcome.