Hi.
Hello, how may I be at your service today?
  I need to change my existing reservation as my exams got postponed, Can you please help me with that?
May I know your name please to check the status of your reservation?
Eric Green here.
Thank you. Please stay online for a while, I will check your reservation status and let you know.
Sure.
Sorry, there is no reservation matching with your name in our portal to make changes further.
No issue, thanks for the information.
Thank you for reaching us.