You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Myself Barbara White.

ASSISTANT: How can I assist you for the day?

USER: Can you help me to book flight ticket from DCA to OAK?

ASSISTANT: Sure, may I know your travelling dates, please?

USER: My trip dates are Nov 21 and Nov 23.

ASSISTANT: Do you have any particular time for departing and returning?

USER: I want to return in the afternoon.

ASSISTANT: May I know your connection limit?

USER: I am comfortable with any connection.

ASSISTANT: Do you have any other specifications?

USER: No.

ASSISTANT: There are no flights found on this route as per your travel dates.

USER: Ok, not a problem. Thank you for the information.

ASSISTANT: Thank you for reaching us.