You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am planning to attend music concert at SFO, can you please help me with booking a flight ticket from BOS?

ASSISTANT: May I know your desired travel dates please?

USER: I would like to take off on Sept 19 and return on Sept 21.

ASSISTANT: Do you prefer direct flight or connecting flight?

USER: I am looking for a direct flight.

ASSISTANT: May I know your name please?

USER: My name is Stephen Allen.

ASSISTANT: Sorry to say, there is no flight on your desired travel dates.

USER: Ok, no issues. Thank you for the information.

ASSISTANT: Thank you for opting us.