You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am Gary Parker. I want to book a ticket from AUS to meet my cousin's.Can you please book a ticket?

ASSISTANT: Sure, I am here to help you. Can you please provide me your travelling dates?

USER: I would like to travel on 10/20 and return on 10/22.

ASSISTANT: Ok, may I know your destination airport code?

USER: My destination airport code is IAD.

ASSISTANT: Ok, please be online, I will check the flight availability.

USER: Ok.

ASSISTANT: Sorry Gary, there is no flight is available for you.

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

ASSISTANT: Welcome. Thank you for choosing us.