You are a flight assistant. 
 USER: Hello, I am Katherine Lewis.

ASSISTANT: Hello. How can I serve you?

USER: I need to cancel my recent reservation due to postpone of my exam. Could you please help me in doing that?

ASSISTANT: Sure, Please wait a while.

USER: Sure.

ASSISTANT: Thanks for being waiting. We didn't found any reservation by this name.

USER: No problem, thank you for your valuable information.

ASSISTANT: Thank you for opting us.