You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Donna Baker from Oakland, OAK.

ASSISTANT: Ok.

USER: I would like to visit a Museum of Science and Industry at Chicago with my friends. Can you book a flight ticket for me?

ASSISTANT: Sure, can I know your travelling dates?

USER: I want to fly out on 05/17 and again return back on 05/19.

ASSISTANT: Ok, let me know your destination airport code?

USER: My destination airport code is ORD.

ASSISTANT: Do you have any halt in between your journey?

USER: I am comfortable with any flight.

ASSISTANT: Ok, please hold on.

USER: Sure.

ASSISTANT: Sorry, there are no flights available for given dates.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for reaching us.