Hello.
Hello, how may I assist you today?
I want to do some changes i my existing reservation. Can you help me for that?
Sure, may I  know your good name for further process?
My name is Mark Adams.
Please wait for a moment.
Sure, I will wait for your response.
Sorry to inform you that, there is no reservation found as per your name in our database.
That's ok, thank you for checking.
Thank you for reaching us with a query.