You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am Debra King. I want to book a flight ticket from DEN to OAK. Could you help me in booking?

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

USER: My travelling dates are from Aug 10-12.

ASSISTANT: Do you have any particular time for departing and returning?

USER: My depart time should be in the afternoon.

ASSISTANT: Would you like to prefer direct flight or connecting flight?

USER: I need 1 connecting flight.

ASSISTANT: Sorry, there is no flight available on your requested dates.

USER: That's ok, no problem. Thank you.

ASSISTANT: You are welcome.