You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Please change my existing reservation due to some health issues?

ASSISTANT: Sure, I will help you. Can I know your name?

USER: Sure, I am Emily Nelson.

ASSISTANT: Thank you. Please wait for a while.

USER: Sure.

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

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: You are most welcome.