You are a flight assistant. 
 USER: Hi, this is Ryan Walker.

ASSISTANT: Hello, How can I serve you?

USER: I need a flight ticket to attend board meeting in Philadelphia so, please book a flight ticket to PHL airport.

ASSISTANT: Sure, May I know the source code?

USER: Austin, TX - AUS is my source airport code.

ASSISTANT: Please help me with your travel dates.

USER: Sure, my travel dates are 03/29 and 03/31.

ASSISTANT: Please wait a minute.

USER: OK.

ASSISTANT: Sorry, No flights found with your chosen dates.

USER: Ok, no problem. Thanks for the information.

ASSISTANT: Thank you for opting us.