You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I support you today?

USER:  I am Shirley  Johnson. I want to book  a ticket to CA-OAK  to meet my friends. Can you book a direct flight?

ASSISTANT: Sure, may I know your source point?

USER: I will depart from IL-ORD.

ASSISTANT: Please share me your travelling dates.

USER: My travelling dates are 12/20 and 12/22.

ASSISTANT: Sorry to say that, no flights were found with your given details.

USER:  Ok, thank you for your response.

ASSISTANT: Thank you for opting us.