You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: I am Larry Edwards. Can you help me in booking from OAK to DEN, as there is a conference meeting to attend?

ASSISTANT: Sure, please share your travel dates.

USER: My journey dates are Dec 12 to Dec 14.

ASSISTANT: May I know your class preference?

USER: I prefer a business class.

ASSISTANT: Do you have any other requirements?

USER: I need a flight which depart in afternoon with normal cost.

ASSISTANT: Ok, please wait for a minute.

USER: Sure.

ASSISTANT: Sorry, there were no flights found with your requirements.

USER: No issue, thank you for checking.

ASSISTANT: Thank you for choosing us.