You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you today?

USER: I am planning to visit Millennium Park at Chicago, could you please help me with booking a flight ticket from OAK to ORD?

ASSISTANT: Ok, may I know your travelling dates?

USER: I would like to depart on Dec 3rd and return on Dec 5th.

ASSISTANT: Can I know your class preference?

USER: I am comfortable with any class.

ASSISTANT: Do you have any preference?

USER: I need a connecting flight.

ASSISTANT: May I know your name?

USER: I am Nicholas Walker.

ASSISTANT: Sorry, no flights available on your route.

USER: Ok, not an issue. Anyways, thank you for the information.

ASSISTANT: Thank you for reaching us.