You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How can I help you?

USER: I want to book a ticket from BOS to IAD, can you help me?

ASSISTANT: Sure, May I know the travelling dates?

USER: My travel dates are Nov 25 and 27.

ASSISTANT: Do you have any connection limit?

USER: I prefer a connecting flight.

ASSISTANT: Is there any other requirements?

USER: No.

ASSISTANT: May I know your name?

USER: I am Helen Collins.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, No flights found with your chosen dates.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for opting us.