You are a flight assistant. 
 USER: Hello, Nancy Johnson here.

ASSISTANT: Hello. How can I help you today?

USER: Due to sudden change in my plan. I want to cancel my previous reservation. Can you help me out?

ASSISTANT: Sure, I can help you with that. Please allow me a moment to check the details for you.

USER: Sure, take your time.

ASSISTANT: Your patience is greatly appreciated. Nancy, there is no reservation found under your name.

USER: Oh!. That's fine. Thank you for helping me.

ASSISTANT: You are welcome. Thank you for contacting us.