You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you today?

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

ASSISTANT: Sure, I am here to help you with this intent.

USER: Thank you.

ASSISTANT: May I know your name please for further process?

USER: Myself Elizabeth Davis.

ASSISTANT: Ok, please be hold on for a moment to check for the availability.

USER: Sure.

ASSISTANT: Sorry Davis, there is no reservation found as per your name to modify your reservation.

USER: No problem, thanks for checking.

ASSISTANT: You are welcome always.