You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you?

USER: Could you please change my existing reservation due to postpone of my exams?

ASSISTANT: Sure, may I know your name to proceed further?

USER: My name is Donna Adams.

ASSISTANT: We regret to inform you that there is no active reservation found on your name to change.

USER: Not a problem, thank you.

ASSISTANT: Thank you for contacting us.