You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist  you?

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

ASSISTANT: Ok, may I know your name?

USER: Myself Anna Clark.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, I did not find any active reservation on your name to change.

USER: No problem, thanks for checking.

ASSISTANT: Most welcome.