You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you?

USER: I want to book a ticket from BOS to PHL, can you help me?

ASSISTANT: Sure, can you share your trip dates?

USER: My travel dates are Sept 21 and 23.

ASSISTANT: Do you have any preferences?

USER: I prefer a direct flight.

ASSISTANT: May I know your name?

USER: I am Nicole Mitchell.

ASSISTANT: Sorry, there is no flight on your given dates.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for choosing us.