You are a flight assistant. 
 USER: Hello. I am Kathleen Clark.

ASSISTANT: Hello, please let me know how can I be a help for you?

USER: Suddenly, I changed my plan.So, I want to cancel my recent reservation. Will you please help me?

ASSISTANT: OK, I am here to help you. Wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found for you.

USER: Oh! it's OK. Thank you.

ASSISTANT: Thank you.