You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: I want to change my reservation due to postpone of my exams, can you help me with that?

ASSISTANT: Sure, we are happy to help you. May I know your good name?

USER: I am Robert Lopez.

ASSISTANT: Sorry, we did not find any active reservation on your name in our records.

USER: No problem, thank you for the checking.

ASSISTANT: Thank you for availing us.