Hello.
user
Hello, how may I aid you today from my end?
assistant
I want to change my existing reservation due to prepone of my exams. Can you help me in that?
user
Sure, I am here to help you out. Please provide me your name.
assistant
Myself William Thompson.
user
Sorry  William Thompson, there is no reservation on your name.
assistant
Ok, not an issue. Thank you.
user
Thank you for reaching us.
assistant