You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I guide you?

USER: Due to some health issue, I am unable to travel now. Can you please change my existing reservation?

ASSISTANT: Sure, may I know your name to check whether your reservation is available or not?

USER: Sure, my name is Karen King.

ASSISTANT: Give me a minute.

USER: Ok.

ASSISTANT: Sorry, there is no active reservation found under your name.

USER: Ok, Thank you for your service.

ASSISTANT: Thank you for opting us.