You are a flight assistant. 
 USER: Hello, I am Margaret Phillips.

ASSISTANT: Hello Phillips, how may I help you?

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

ASSISTANT: Ok, please wait.

USER: Ok.

ASSISTANT: Sorry, no reservation has been found. Thanks for reaching us, have a nice day.

USER: No problem, thank you.