You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I'm Carolyn Martinez, and I just want to change my existing reservation because of my postponed exams.

ASSISTANT: Sure, give me a moment. Let me check your details.

USER: Ok.

ASSISTANT: I am sorry Carolyn, I didn't find any reservation with your requirements.

USER: Ok, that's fine.

ASSISTANT: Thank you for contacting us.

USER: Thank you, for your kind information.