You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I help you?

USER: I am planning to celebrate my birthday in Oakland, so please book a flight ticket from DEN to OAK.

ASSISTANT: Sure, May I know your travelling dates?

USER: My departure day is Nov 24, return day is Nov 26.

ASSISTANT: Do you have any connection limit?

USER: I need a connecting flight.

ASSISTANT: May I know your name?

USER: My name is Nancy Nelson.

ASSISTANT: Sorry, there are no flights found with your data.

USER: No problem, thank you.

ASSISTANT: Thank you.