You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Jerry Martin.

ASSISTANT: Jerry, how can I aid you today?

USER: I am planning to change an existing reservation, due to health issue. Can you please change my reservation?

ASSISTANT: Sure, I am here to help you. Hold on for a moment. Let me check.

USER: Thank you. Sure.

ASSISTANT: Sorry Jerry, there are no flights reserved on your given name formerly.

USER: That's fine. Thank you for your  service.

ASSISTANT: Welcome, thank you for choosing us. Have a great day.