You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I guide you for today?

USER: My name is John Hall, I want to change my reservation as my trip got postponed. Can you change my reservation?

ASSISTANT: Sure, I will help you with that John Hall. I regret to say this John Hall, there is no active reservation with your name to change.

USER: Ok, thank you for the information.

ASSISTANT: You are welcome.