You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I guide you for today?

USER: I need a connecting flight for my journey to attend an event in Oakland in the month of December. Can you please help me in booking a flight ticket with the normal-cost airlines?

ASSISTANT: Can you please share on what dates you are willing to travel?

USER: I would like to start my journey on Dec 7 and need to have a return flight on Dec 9.

ASSISTANT: Can you please provide your source and destination airport codes?

USER: Sure, my source and destination airport codes are LAS and OAK.

ASSISTANT: Do you have any class preferences?

USER: I am comfortable with any of the class.

ASSISTANT: Do you have any other requirements that you are looking for?

USER: No, thanks for asking.

ASSISTANT: Can you please provide your name to proceed further?

USER: Sure, my name is Raymond Walker.

ASSISTANT: Sorry, there are no flights available at your request.

USER: Not a problem, anyways thank you for the information.

ASSISTANT: Thank you for contacting us, have a nice day.