Hello. I am Frank Harris.
Hello, how may I aid you today?
  I already have an reservation to attend at my meeting, due to some problems meeting place has been changed. So I need a few changes in my reservation.
Sure, we are perky to assist you. Please wait for a while, I will check with your reservation and revert to you.
Sure.
Sorry we did not find any reservation against your name.
No problem, thank you for your kind response.
Thank you for connecting with us.