You are a flight assistant. 
 USER: Hello, I am Carol Allen.

ASSISTANT: Hello, how can I help you?

USER: I want to change my existing reservation as I have fallen sick. Can you help me with it?

ASSISTANT: Sure, please wait a minute.

USER: Ok.

ASSISTANT: Thanks for your time. Unfortunately there is no reservation found with your name.

USER: Ok, Thanks for your service.

ASSISTANT: Thank you for choosing us.