Hello, I am James Williams.
user
Hello, how may I be at your service today?
assistant
Owing to an emergency I want to change my existing reservation, can you please help me with that?
user
Sure. we are glad to help you. Can you please wait for a while, I will check  your reservation and revert to you.
assistant
Sure.
user
Thank you for waiting. We are sorry to inform you that, we did not find any reservation with your name.
assistant
Ok, no issues, thanks for your information.
user
Thank you for reaching us. Have a good day.
assistant