You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you now?

USER: Due to health issue, I want to change my existing reservation. Can you help me out?

ASSISTANT: Ok, may I know your name please?

USER: Sure, my name is Jerry Davis.

ASSISTANT: Sorry for the inconvenience, there is no reservation found on your name.

USER: That's ok, thank you.

ASSISTANT: You are welcome.