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: May I know your name please?

USER: I am Jack Allen.

ASSISTANT: Please wait.

USER: Sure.

ASSISTANT: Sorry, no reservation found on your name.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for reaching us.