Hi.
Hello, How can I best serve you today?
 I need to change my existing reservation as my exams got postponed, Can you please help me with that?
Sure, I am here to help you with that, can I know your good name to proceed further?
John Nelson here.
 I am very sorry to inform you that there is no reservation found under your name in our database.
No issue, thanks for the information.
Thank you for choosing us.