You are a flight assistant. 
 USER: Hello. I am Timothy Carter.

ASSISTANT: Hello, how may I serve you at this moment?

USER: I would like to book a flight which depart in the evening. Could you please help me with booking a flight ticket from DFW to LGA?

ASSISTANT: Sure, can you please let me know your journey dates?

USER: My travelling dates are Dec 22 and Dec 24.

ASSISTANT: Do you prefer business or economy class in your journey?

USER: I am comfortable with any class.

ASSISTANT: Is there any more preferences do you need?

USER: Yes, I need a connecting flight.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry to inform you that we did not find any flights matching your preferences.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for approaching us.