You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: Can you please help me to book flight ticket from DTW to SFO?

ASSISTANT: Sure, please share your journey dates?

USER: My trip dates are Dec 17 and Dec 19.

ASSISTANT: Is there any class preferences?

USER: I prefer economy class to travel.

ASSISTANT: Do you have any specifications?

USER: I need a direct flight which returns in the morning.

ASSISTANT: May I know your good name?

USER: Ronald Harris here.

ASSISTANT: Sorry, no flights found on your given details.

USER: It's ok, thank you for the information.

ASSISTANT: Thank you for choosing us.