You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: Stephanie Martinez here. I want to change my existing reservation due to postpone of my exams. Can you help me in that?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Sorry to inform you that there is no reservation found on your name.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you.