You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I assist you?

USER: I want to change my existing reservation due to bad health issues. Can you help me with that?

ASSISTANT: Sure, May I know your name?

USER: I am Lisa Lee.

ASSISTANT: Please wait a second.

USER: Sure.

ASSISTANT: Sorry, No reservation found on your name.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for opting us.