Hello.
Hello, how can I help you today?
I need to do some modifications in my existing reservation, can you help me out?
Sure, please tell me your good name.
Myself Jennifer Campbell.
Please wait, I will get back to you.
Take your own time.
 I have checked and seen that there is no reservation found under your name.
That's ok, no problem.
Thank you so much.
Thank you for checking my reservation details.
Most welcome.