You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I serve you?

USER: I am Joshua Harris. I would like to go for museum at Denver, DEN. Can you please book a ticket on 12/02?

ASSISTANT: Sure, May I know the source code?

USER: Source code is Boston, BOS.

ASSISTANT: Please help me with your return date.

USER: Return is on 12/04.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Thanks for sharing your details, we are unable to provide flight in between your journey routes due to heavy snowfall at destination airport. Thank you for choosing us.

USER: No problem. Thank you.