You are a flight assistant. 
 USER: Hi, I am William Hall.

ASSISTANT: Hello, how may I be at your service today?

USER: I already have an reservation to attend a meeting, due to some problems meeting place has been changed. So I need a few changes in my reservation. Can you help me with that?

ASSISTANT: Sure, we are glad to help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry we did not find any reservation on your name.

USER: Ok, no issues. Thanks for your excellent service.

ASSISTANT: Thank you for opting us. Have a good day.