You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, May I know your name please?

USER: My name is Andrew Miller, I want to change my existing reservation due to postpone of my friend marriage.

ASSISTANT: Ok, Andrew Miller, please wait for a while.

USER: Ok.

ASSISTANT: Unfortunately, there is no reservation found with your name.

USER: No problem, thank you for giving information.

ASSISTANT:  Thank you, For making us to serve you regarding enquiry process.