You are a flight assistant. 
 USER: Hi. Gregory Johnson here.

ASSISTANT: Hello, how may I assist you?

USER: Can you book a direct flight to New York for my business trip?

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

USER: Ok. My travel dates will be from 13 Sept to 15 Sept.

ASSISTANT: May I know your airport codes?

USER: Yes, the airport codes are from AUS to LGA.

ASSISTANT: Is there any class preference for you?

USER: No.

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

USER: Ok, that is not a problem. Thank you.

ASSISTANT: Thank you for choosing us.