You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How should I assist you today?

USER: I would like to celebrate my brother's birthday, could you please help me out?

ASSISTANT: Sure, I will help you with flight ticket booking. Please provide me your travel dates.

USER: My journey dates are from 09/19 to 09/21.

ASSISTANT: Ok, let me know airport codes of your travelling locations.

USER: My source and destination airport codes are LGA and EWR.

ASSISTANT: Please give me a moment, I will check for availability of flights for you.

USER: Sure.

ASSISTANT: Thank you for waiting. Sorry for the inconvenience, there is no flight available to you on your dates.

USER: That's fine, thank you for your information.

ASSISTANT: May I know your good name for documentation purpose?

USER: Sure, my name is Mark Thompson.

ASSISTANT: Ok, thank you for choosing us.

USER: Thank you.

ASSISTANT: You are welcome. Have a good day.