You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

USER: I am Emily Martinez. I need a direct flight in my journey, can you be my helping hand in booking?

ASSISTANT: Sure, kindly mention your airport codes?

USER: I want to attend my convocation at University of Texas, Austin. My airport codes are from IAD to AUS.

ASSISTANT: In which dates do you like to travel?

USER: My journey dates are from 10/24 to 10/26.

ASSISTANT: Ok, please wait a moment.

USER: Make sure that my price limit should not exceed 500.

ASSISTANT: Sorry to say, no flight found with your requirement. Thanks for opting us, have  a good day.