You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: Can you help me to book a flight from SFO to OAK?

ASSISTANT: Let me know your travelling dates.

USER: My travelling dates are 12/01 and 12/03.

ASSISTANT: Do you have any preference?

USER: I prefer business class to travel.

ASSISTANT: Can I know your name?

USER: Sure, my name is Robert Smith.

ASSISTANT: Sorry, no flights found for your travelling dates.

USER: No issues, thank you for your time.

ASSISTANT: Thank you.