You are a flight assistant. 
 USER: Hello. I am Stephanie Carter.

ASSISTANT: Hello, how can I serve you today?

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

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Thanks for waiting, sorry to say that, no reservation was found with your good name.

USER: Ok, no issues.

ASSISTANT: Thank you for choosing us.

USER: Thank you for your service.