You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I amend you the best today?

USER: My name is Kenneth Hernandez, I want to change my existing reservation due to postpone of my interview.

ASSISTANT: Ok, I can help you to change your reservation. Please wait, I will check and update you.

USER: Sure.

ASSISTANT: Sorry, no reservation has been found with your name to change.

USER: No problem, thanks for your help.

ASSISTANT: Thanks for approaching us, have a nice day.