You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you?

USER: I want to change my reservation due to health issue.

ASSISTANT: Ok, may I know your good name please?

USER: Sure, my name is Margaret Campbell.

ASSISTANT: Sorry, there is no active reservation found on your name in our database to change.

USER: Ok, no problem. Thank you for checking.

ASSISTANT: Thank you for contacting us.