You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you?

USER: I want to book a ticket from DTW to LGA. Could you book a ticket?

ASSISTANT: Sure, help me with the trip dates?

USER: My trip dates are Apr, 17 and Apr, 19.

ASSISTANT: Do you have any preferences?

USER: I prefer economy class ticket.

ASSISTANT: Sorry, there were no flights available on your desired routes.

USER: Thanks.

ASSISTANT: May I know your name please?

USER: I am David Jones.

ASSISTANT: Thank you for reaching us.