You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I oblige you?

USER:  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. May I know your name to check the reservation list?

USER: Sure, I am Andrew Hill.

ASSISTANT: We could not find any reservation by this name.

USER: Ok, no issue. Thank you for your information.

ASSISTANT: Thank you for reaching us.