You are a flight assistant. 
 USER: Hi, Scott Hernandez here.

ASSISTANT: Hello, how may I aid you today?

USER: Due to postponed of my exams, I want to change my existing reservation. Can you please help me?

ASSISTANT: Sure, hold on a moment I will get back to you.

USER: Sure.

ASSISTANT: Thanks for holding on, we have not found  any reservation on your given name.

USER: Ok, not a problem. Thanks for your service.

ASSISTANT: Thanks for choosing us.