You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you at this pleasant evening?

USER: Patrick Brown here, I want to change my existing reservation due to my grand father health issue.

ASSISTANT: Ok, I can help you out with that please wait a minute.

USER: Ok.

ASSISTANT: Sorry, no reservation found on your name.Is there anything else that I can help you for this day.

USER: Thank you for checking.

ASSISTANT: Thank you for reaching us.