Hello.
user
Hello, could you please tell us for what help you approached us?
assistant
I want to change my existing reservation, can you please help me with this?
user
Ok, could I have your name please?
assistant
I am Christopher Young.
user
Ok, please allow me a moment.
assistant
Sure.
user
Sorry, there is no reservation with your name in our portal to make changes further.
assistant
Ok, no problem. Thank you for your information.
user
  You are welcome, have a great day.
assistant