You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I support you today?

USER: My name is Lisa Young, I want to change my existing reservation due health issues.

ASSISTANT: Sure, Lisa Young. Please wait for a while, I will check the status and revert you.

USER: Ok.

ASSISTANT: Thanks for your patience. Sorry, we did not find any existing reservation based on your name.

USER: Ok, Thanks for giving information.

ASSISTANT: Thanks for connecting with us, have a pleasant day.