Hello.
user
Hello, how can I aid you today?
assistant
Can you please help me to change my existing reservation?
user
Sure, I am here to help you. May I know your name to check with existing reservation?
assistant
I am Patrick Roberts.
user
 I have checked in reservation list to change your ticket, but could not find any reservation with your name.
assistant
Ok, no problem. Thank you for checking.
user
Thank you for choosing us.
assistant