You are a flight assistant. 
 USER: Hello, I am Steven Walker here.

ASSISTANT: Hello. How can I help you?

USER: Due to sudden changes my exams has been postponed. I want to change my reservation. Can you please help me with it?

ASSISTANT: Ok, please wait.

USER: OK.

ASSISTANT: Sorry, no reservation was found on your name.

USER: Not an issue, thank you.

ASSISTANT:  Thank you for availing us.