You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I oblige you for the day?

USER: I am Kevin Williams. I want to change my reservation, due to postponement of concert to be held at the place where I wanted to visit, can you please take your precious time for helping me?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

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

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for contacting us.