You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Helen Clark.

ASSISTANT: How can I help you?

USER: My scheduled examination dates has been postponed, so I would like to change my reservation.

ASSISTANT: Sure, give me a minute. Let me check the details.

USER: Sure.

ASSISTANT: Sorry Clark, there are no reservations found on your name.

USER: That's ok. Thank you for the help.

ASSISTANT: Welcome.