You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: Larry Davis here. 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 in changing my booking?

ASSISTANT: Sure, wait a while. There is no reservation on your name, Larry.

USER: Sure. No problem, thanks for your help.

ASSISTANT: Thanks for reaching us.Have a great day.

USER: Thank you.