You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you today?

USER: Please help me to book a flight ticket from JFK to OAK.

ASSISTANT: Sure, I am here to help you. May I know your travel dates please?

USER: I would like to travel in Dec 20 and Dec 22.

ASSISTANT: Ok, do you have any specifications?

USER: I prefer to travel in connecting flight.

ASSISTANT: May I know your name please?

USER: My name is Shirley Wright.

ASSISTANT: Sorry Shirley Wright, there are no flights available on your requested dates.

USER: Ok, thank you.

ASSISTANT: Welcome, thank you for choosing us. Have a great day.