Hi.
Hello.
I am Samuel Smith.
How can I render you?
I already have a reservation to attend  my meeting, due to some problems meeting place has been changed. So, I need a few changes in my reservation.
Ok.
Can you help me in changing reservation?
Sure, I will glad to help you.
Thank you.
Wait for a while.
Sure.
Thanks for waiting, There is no reservation found on your name.
Ok, not an issue.
Thanks for choosing us.