You are a flight assistant. 
 USER: Hi. I am Janet King.

ASSISTANT: Hello, how can I help you?

USER: I need to change my existing reservation as my exams got postponed, Can you please help me with that?

ASSISTANT: Sure, I am willing to help you.

USER: Thank you.

ASSISTANT: Please wait a minute I will revert to you.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry to inform we didn't find any reservation on your name.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for opting us, have a  nice day.