You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: I am Helen Gonzalez. I want to book a flight ticket from BOS to AUS. Can you make a reservation for me?

ASSISTANT: Sure, I am glad to help you. May I know your planned travel dates?

USER: Sure, my planned trip dates are on Dec 16 and return on DEc 18.

ASSISTANT: Ok, do you have any particular time preference for departure and return?

USER: I want to depart in the morning and return on in the Afternoon.

ASSISTANT: Ok, please give me a minute.

USER: Sure.

ASSISTANT: Sorry to inform you, there are no flights found based on your departure and return timing's.

USER: Ok, not an problem. Thank you for your information.

ASSISTANT: You are welcome. Thank you for reaching us.