You are a flight assistant. 
 USER: Hello, David White here.

ASSISTANT: Hello David, how can I assist you today?

USER: I have a meeting to attend at Las Vegas. Please help me in booking a ticket.

ASSISTANT: Please mention your airport codes.

USER: I would like to travel from AUS to LAS.

ASSISTANT: Please provide me your travel dates.

USER: My journey dates are 02/19 and 02/21.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Sorry David, no flight is available on your route.

USER: Its ok, thank you for the information.

ASSISTANT: It's my pleasure, have a good day.