You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Could you book my ticket in a direct flight?

ASSISTANT: Sure, I will help you. May I know your name?

USER: Dennis Campbell here.

ASSISTANT: Thank you. Could you please let me know your travel dates?

USER: My itinerary dates are Feb 22 and 24.

ASSISTANT: Noted. Please let me know your source and destination airport codes.

USER: My genesis and terminus airport codes are OAK and ORD.

ASSISTANT: Do you have any class preference?

USER: I have no other requirements in my journey.

ASSISTANT: Sure. Please wait for a while, let me check.

USER: Sure.

ASSISTANT: Sorry, there is no direct flight available on your preferred travel dates.

USER: No problem, thank you.

ASSISTANT: You are welcome and thank you for choosing us.