You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: Jonathan Wilson here. I just want to change my existing reservation,due to some health issues. Can you please help me out with it?

ASSISTANT: Ok, I am here to help you about that. Please wait for a while.

USER: Thank you. Ok, sure.

ASSISTANT: Sorry, no reservation found on your name to change.

USER: Ok not a problem. Anyways, thank you.

ASSISTANT: Thank you for reaching us.