You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Michelle Thomas.

ASSISTANT: How may I help you?

USER: Due to sudden changes, my exams has been postponed. Can you please change my reservation.

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, there is no reservation matching with your name in our portal to make changes further.

USER: Ok, not an issue. Thank you.

ASSISTANT: Most welcome.