You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. Can I know your name?

USER: My name is Kathleen Harris.

ASSISTANT: How may I aid you?

USER: I'm planning to visit Museum of Science and Industry which is located in Chicago, so I am searching for a flight from OAK to ORD.

ASSISTANT: Ok, can I know your preferable dates of travel?

USER: My preferable dates are from 11/22 to 11/24.

ASSISTANT: Please hold on for a moment, let me check.

USER: Ok, please check.

ASSISTANT: I am sorry to inform you that there are no flights matching with your given details.

USER: That's so sad to hear. Thank you for your valuable time.

ASSISTANT: Thank you, have a good day.