You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I guide you today?

USER: Due to my ill health, I want to change my existing reservation. Could you please help me out?

ASSISTANT: Sure, could I know your name please?

USER: My name is Amy Carter.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, I could not found any reservation by your name.

USER: Ok, no issue.

ASSISTANT: Thank you for choosing us.

USER: Thank you for your response.

ASSISTANT: Welcome.