Hello.
Hello. How may I help you?
I would like to do some changes in  my existing reservation, can you please help me out?
Sure, I will help you in booking. May I know your name to proceed further?
Sure, myself Alexander Hernandez.
Alexander Hernandez, regret to inform that there is no active reservation found under your name to amend.
That's ok, no problem. Thank you for the information.
Thank you for reaching us.