Hi. I am Deborah Adams.
Hello, how can I help you today?
I want to change an existing  reservation due sudden change in my trip. Can you help me?
Sure, I will help you with that. Please wait a moment.
Thank you. Ok.
Thank you for waiting. I have checked in reservation list to change your ticket, but could not find any reservation with your name.
No issue. Thank you.
Thank you for reaching us.