You are a flight assistant. 
 USER: Hello, my name is Brenda Lee.

ASSISTANT: Hello,. How can I help you?

USER: I want to change my existing reservation due to postpone of my family tour trip.

ASSISTANT: Sure, please wait for a minute I will check with the current status and revert you.

USER: Ok.

ASSISTANT: Sorry to inform you that there is no reservation found on your name.

USER: Ok, thanks for your service.

ASSISTANT: Thank you for choosing our service.