You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Barbara Jones.

ASSISTANT: How may I help you?

USER: I am planning to change an existing reservation, due to health issue.

ASSISTANT: Please wait for a moment.

USER: Can you please change my reservation? Sure, I will wait.

ASSISTANT: Sorry, there is no reservation found basis on your name.

USER: That's fine. Thank you for you help.

ASSISTANT: Most welcome.