You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: I want to change my reservation due to postponed of my exam, so please help me in changing.

ASSISTANT: Sure, I am happy to help you.

USER: Thank you.

ASSISTANT: May I know your good name to proceed further?

USER: Sure, I am Ryan Lopez from San Francisco.

ASSISTANT: Ok, please wait for a while. I will check your status and revert you.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no active reservation on your name in our data.

USER: No issues, thank you.

ASSISTANT: Thank you for opting us.