Hello.
Hello, How can I provide assistance to you?
I am Melissa Clark. I would like to change my reservation, can you please help me out?
Sure. I am perky to help you. Please wait for a  while, I will check the previous reservation with your name.
Ok.
Thank you for being patience. I am here to say that, there is no reservation available with your name.
Ok, no problem thank you for your services.
Thank you for availing us.