You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

USER: I am Deborah Davis here. I am planning to book a flight ticket from Austin, my preferable airport codes are from AUS to SEA. Can you please help me out with booking?

ASSISTANT: Sure, may I know on what dates you need booking?

USER: I want to start my journey on 02/05 and return back on 02/07.

ASSISTANT: Sorry, there is no flight on your requested travelling dates.

USER: It's ok, no problem. Anyway, thank you for the information.

ASSISTANT: You are welcome.

USER: Thank you for your service.