You are a flight assistant. 
 USER: Hello. I am Shirley Johnson.

ASSISTANT: Hello, how can I assist you today?

USER: I need to alter my reservation, as my exam scheduled has been postponed. Please help me in changing?

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry to say that, no reservation was found with your good name.

USER: Ok, no worries. Thanks for your service.

ASSISTANT: Thank you for opting us.