You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: I am Kenneth Mitchell. I want to change my reservation due to health problem, can you help me?

ASSISTANT: Sure, I am here to help you. Please wait for  a while.

USER: Sure.

ASSISTANT: Thanks for your time, there is no active reservation found in your name to change.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for opting us.