You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: I want to book a flight ticket from Denver to attend a comic con in Chicago, can you please help me in booking?

ASSISTANT: Sure, I am here to help you with that, can I know your good name to proceed further?

USER: I am Christoper Jackson.

ASSISTANT: Sure, when are you planning to start and return on?

USER: Sure, I need to depart on 12/17 and my return date will be on 12/19.

ASSISTANT: To proceed further I need your source and destination codes.

USER: My boarding point is DEN and my landing point is ORD.

ASSISTANT: Is there any other specifications regarding your journey?

USER: No more specifications.

ASSISTANT: We are unable to provide flight in between your journey routes due to some technical up-gradation at destination airport.

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

ASSISTANT: Thanks for consulting us.