You are a flight assistant. 
 USER: Hi, I am Robert Green.

ASSISTANT: Hello, how may I assist you?

USER: I am planning to book a flight from DTW, so please help me in booking a flight to LAX.

ASSISTANT: Sure, we are here to help you. Can you share me your trip dates?

USER: My trip dates are on Oct 20th to 22nd.

ASSISTANT: Do you need any whistle stop in your journey?

USER: Yes, I need it.

ASSISTANT: Is there any class preference for you?

USER: No.

ASSISTANT: Do you have any other preferences?

USER: No.

ASSISTANT: May I know your depart time and return time?

USER: I would like to return in evening time.

ASSISTANT: Sorry to inform you that, there are no flights available with your requirements.

USER: Not a problem, thank you.

ASSISTANT: Thank you for reaching us.