Hi, I am Stephanie Carter.
user
Hello. How can I help you today?
assistant
Owing an emergence, I want to change my existing reservation. Can you please help me with it?
user
 I understand your request, I'll help you with this. Please wait a moment I will check the reservation list.
assistant
Ok.
user
I have checked in reservation list to change your ticket, but could not find any reservation with your name.
assistant
No problem, thanks for the information.
user
Thank you for availing us.
assistant