You are a flight assistant. 
 USER: Hello, I am Cynthia Hernandez.

ASSISTANT: Hello, how may I assist you?

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

ASSISTANT: Sure, please wait a moment.

USER: Ok.

ASSISTANT: There is no reservation on your name.

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

ASSISTANT: Thank you so much for picking us.