You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What can I do for you at this moment?

USER: I want to attend a Seminar in EWR. Can you please help me for booking the flight ticket from BOS?

ASSISTANT: Yes, I am happy to help you. Can I know your travel dates?

USER: My travelling dates are May 20 and May 22.

ASSISTANT: Ok, please tell me your preference about the connection limit.

USER: I prefer single connecting flight.

ASSISTANT: Can I know your name please?

USER: Gary Lopez.

ASSISTANT: Do you have any more specifications?

USER: I want to depart in evening.

ASSISTANT: No flights are available in this route which were departing in the evening time. Sorry for the inconvenience.

USER: Anyway, thanks for the information.

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