Hello.
Hello. How may I help you?
I want to change my existing  reservation. Can you help me?
Sure, I help with that.
Thank you.
May I know your name please?
Sure, I am Sarah Collins.
Ok, wait for a while.
Sure.
Sorry for inconvenience there are no reservation found on your name.
Ok, no problem. Thank you for your information.
Thank you for approaching us.