You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: I am Betty Perez. I would like to visit New York city to spend my vacation holidays with childhood friends. So please help me with flight ticket booking.

ASSISTANT: Sure, I am here to help you. Could you please tell me your travel dates?

USER: Thank you. I need to travel on dates of 09/21 and 09/23.

ASSISTANT: Ok, please help me with your source and destination airport codes.

USER: Sure, I would like to travel from SEA to EWR because these are the only airports which are near to my travelling locations.

ASSISTANT: Ok, please wait for a moment.

USER: Sure, take your time to check.

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

USER: Oh! It is sad to hear. Anyway, I will choose another agency this time. Thank you for your valuable time.

ASSISTANT: You are welcome and thank you for choosing us.