You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you now?

USER: I want to change my reservation due to postpone of my exams, can you help me with that?

ASSISTANT: Sure, I will help you with that. May I know your good name?

USER: I am John White.

ASSISTANT: Sorry, there is no active reservation on your name in our data.

USER: No issues, thank you for checking.

ASSISTANT: Thank you for opting us.