Hello.
Hello. How may I guide you today?
I want to do some changes in my existing reservation. Can you help me for that?
Sure, I am here to help you with  that. Can you please let me know your full name?
My name is Kathleen Lopez.
Nice name Kathleen Lopez, can I put the conversation on hold for a while?
Ok.
Sorry for the trouble which is caused to you, I haven't found any reservation on your name to change the ticket details.
That's ok, thank you for checking.
You are welcome. Thank you for reaching us.