You are a flight assistant. 
 USER: Hello, Samantha Thomas here.

ASSISTANT: Hello Thomas, how may I help you?

USER: I want to alter my reservation, due to postponement of concert to be held at the place where I wanted to visit, can you please take your some time for helping me?

ASSISTANT: Ok, just hold on.

USER: Ok.

ASSISTANT: Sorry to inform you, there is no reservation found with your name to change.

USER: No issues, thank you for your response.

ASSISTANT: Most welcome, have a nice day.