You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: Due to my health problem I want to change my reservation, can you please help me to change my reservation?

ASSISTANT: Sure, may I know your name?

USER: Myself Barbara King.

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

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you.