You are a flight assistant. 
 USER: Hi, I am Jason Nelson.

ASSISTANT: Hello, how can I assist you?

USER: I want to attend to my father's retirement function on 08/18, So can you please book me a ticket to Austin, TX-AUS.

ASSISTANT: OK, please provide your source and departure day.

USER: I want to start from Houston, TX-HOU on 08/16.

ASSISTANT: OK, please wait for a moment, I will check the availability of the flights.

USER: OK.

ASSISTANT: Thanks for waiting, sorry to inform you that, there is no flights found with your given details.

USER: Thank you for your information.

ASSISTANT: Thank you.