Hello. I am David Hall.
user
Hello, how may I help you today?
assistant
I am planning to change an existing reservation, due to health issue. Can you please change my reservation?
user
Sure, I am here to help you.
assistant
Thank you.
user
Sorry Hall, there is no reservation found as per your name to change it.
assistant
That's fine, thank you for your service.
user
You are welcome.
assistant