You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Paul King.

ASSISTANT: How can I assist you?

USER: Due to some health issues, I would like to postpone my journey. Can you please change my existing reservation?

ASSISTANT: Ok, please wait.

USER: Ok.

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

USER: Its ok, thank you for the information.

ASSISTANT: Most welcome.