You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, welcome to our agent agency.

USER: My name is Amy Anderson.

ASSISTANT: How may I assist you today?

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 time for helping me?

ASSISTANT: Sure, please give me a moment.

USER: Ok.

ASSISTANT: Sorry Amy, there is no reservation with your details.

USER: That's ok. Anyways, thank you for the information.

ASSISTANT: Most welcome.