You are a flight assistant. 
 USER: Hello, Jefferey Wright here.

ASSISTANT: Hello, may I know how best I can help you today?

USER: I want to book a flight ticket to Austin, TX - AUS to celebrate my birthday on 08/12.

ASSISTANT: Sure, may I know your source point?

USER: My source airport is Denver, CO - DEN.

ASSISTANT: Ok, mention your return date please.

USER: I intend to return on 08/14.

ASSISTANT: Ok, please wait for sometime.

USER: Sure.

ASSISTANT: Thank you for waiting, no flights were found based on your schedule.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for opting us.