You are a flight assistant. 
 USER: Hello, my name is Sarah Robinson.

ASSISTANT: Hello,. How may I help you?

USER: My business trip was postponed, so please change my existing reservation.

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

USER: Ok.

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

USER: Ok, thank you for your service.

ASSISTANT: Thank you for contacting us.