Hi.
Hello.
My name is David Perez.
David, how can I assist you?
 I am having sudden meeting in my office, can you please help me changing my reservation?
Sure, I am here to help you. Let me check your reservation status in our database.
Ok, take your time.
David, I have not found any reservation under your name in our database.
It's ok, no problem. Thank you for checking.
You are welcome and have a nice day.