You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Justin Williams here.

ASSISTANT: Is there any help that you need from our agency?

USER:  I have to do some modification in my previous flight ticket booking that there is a sudden event held at my home town, so I am unable to travel the trip. can you please help me out with changing of my reservation?

ASSISTANT: Sure, I am happy to help you in that flight ticket modification. Please give me a moment.

USER: Sure.

ASSISTANT: I am happy to say that you reservation found, can I know your modified travel dates?

USER: I would like to take off on 12/24 and return on 12/26.

ASSISTANT: Can I know your airfield location codes?

USER: My source airport code is LAS and destination airport code is AUS.

ASSISTANT: Please wait for a moment. According to your information, I have found a flight with single stop over in your journey with a minimum fare of 100 is provided by AA airlines. Shall I proceed with this?

USER: Please confirm the booking.

ASSISTANT: Ok, the ticket booking is done in 1011 with a new flight for your journey. Enjoy your trip.

USER: Thank you for your help.

ASSISTANT: You are most welcome.