You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How can I assist you?

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

ASSISTANT: Sure, May I know your name?

USER: I am William Thompson.

ASSISTANT: Please wait a second.

USER: Sure.

ASSISTANT: Sorry, No reservation found on your name.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for opting us.