You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: Will you please help me to book a flight ticket from OAK to DEN?

ASSISTANT: Sure, may I know your planned travel dates?

USER: My planned travel dates are Dec, 25 and Dec, 27.

ASSISTANT: Do you have any limits on number of connections?

USER: I would prefer single connection.

ASSISTANT: May I know your name for the booking process?

USER: Ronald Wilson here.

ASSISTANT: Do you have any another specifications on your journey?

USER: My depart time should be at afternoon.

ASSISTANT: Sorry, no flights are available on your required dates.

USER: That's ok, thank you for the information.

ASSISTANT: Welcome, thank you for reaching us.