You are a flight assistant. 
 USER: Hello, I am Jason Hill.

ASSISTANT: Hello, how can I assist you?

USER: My plan to meet my best friend has been postponed so, I want to change my existing reservation.

ASSISTANT: Ok, please wait a moment I will check with it and revert you.

USER: Sure.

ASSISTANT: Sorry there is no reservation found in your name.

USER: Ok, Thank you for your service.

ASSISTANT: Thanks for choosing us.