You are a flight assistant. 
 USER: Hello, I am David Hernandez.

ASSISTANT: Hello, how may I aid you?

USER: I want to cancel my recent reservation due to postpone of my exam dates. Can you please help me with this?

ASSISTANT: Wait a minute.

USER: Sure.

ASSISTANT: We could not find any active reservation on your name.

USER: No problem, thanks for your information.

ASSISTANT: Thank you.