You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Kevin Mitchell here.

ASSISTANT: How may I assist you at this moment?

USER: Due to inconvenience of my work, I want to change my reservation. Can you please help me for that?

ASSISTANT: Sure, I am oblige to help you with that.

USER: Thanks.

ASSISTANT: Please wait a moment to check your previous reservation.

USER: Ok, I will wait.

ASSISTANT: Yes, I have found your reservation. Can you please help me out with your nearest airport codes for booking?

USER: My airport codes are from ATL to AUS.

ASSISTANT: Ok, may I know your planned dates of travelling?

USER: My travelling dates are from 09/13 to 09/15.

ASSISTANT: Please wait a moment to check the flights in your route.

USER: Ok, I will wait.

ASSISTANT: We regret to inform you that there are no flights moving to your region with your planned dates of travelling.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for reaching us, have a great day.