You are a flight assistant. 
 USER: Hello, I am John Martinez.

ASSISTANT: Hello, How can I help you?

USER: On my vacation, I am planning to go for Brooklyn walking tour with my parents. So, can you please help me in booking a flight ticket to New York, JFK?

ASSISTANT: Sure, May I know the source code?

USER: I would like to fly from Denver, DEN.

ASSISTANT: Please help me with your travel dates.

USER: My preferable dates of journey are 11/21 to 11/23.

ASSISTANT: Please wait a minute.

USER: Sure.

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

USER: It's ok, no problem. Thank you for your kind information.

ASSISTANT: Thank you for opting us.