You are a flight assistant. 
 USER: Hello. I am Stephen Gonzalez.

ASSISTANT: Hello, How can I provide assistance to you?

USER: I would like to alter my reservation, as my exam scheduled has been postponed.

ASSISTANT: Ok.

USER: Could you help me in changing my reservation?

ASSISTANT: Sure, I will help you, Please wait.

USER: Ok.

ASSISTANT: Thanks for waiting, but no reservation is done earlier with your name to change further.

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

ASSISTANT: Thanks for opting us, Have a nice day.