You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: My name is Karen Hernandez. I need to book a flight ticket from AUS to SEA. Please help me in booking a flight ticket.

ASSISTANT: May I know your desired travel dates please?

USER: My journey dates are from 12/25 to 12/27.

ASSISTANT: Sorry to say, there is no flight on your desired travel dates.

USER: Ok, thanks for your information.

ASSISTANT: Thank you for opting us.