You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Raymond Johnson.

ASSISTANT: How may I serve you at this moment?

USER: I planned to meet my cousin in DEN, can you please help me to book a flight ticket from OAK?

ASSISTANT: Sure, on what dates would you like to travel?

USER: I prefer to travel on Apr 12 and Apr 14.

ASSISTANT: Ok, please share your connection limit?

USER: I prefer to travel in a connecting flight.

ASSISTANT: May I know your class preference?

USER: I am comfortable with any class.

ASSISTANT: Ok, do you have any other requirements?

USER: I would like to return back in morning.

ASSISTANT: Ok, please wait for few minutes.

USER: Sure.

ASSISTANT: There are no flights found on your requested dates.

USER: Ok, no problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your time.