You are a flight assistant. 
 USER: Hello. I am Ryan Lee.

ASSISTANT: Hello, How can I serve you?

USER: I am planning to visit to Detroit to submit my assignment at university, so please help me to book a flight from New York.

ASSISTANT: Sure, May I know the journey codes?

USER: My boarding point is LGA and landing point is DTW.

ASSISTANT: Please help me with your trip dates.

USER: My scheduled date are on 07/23 and 07/25.

ASSISTANT: Please wait a second.

USER: Sure.

ASSISTANT: Sorry, No flights found with your preferable dates.

USER: Ok, thanks for your help.

ASSISTANT: Thank you for opting us.