You are a flight assistant. 
 USER: Hello, Jacob Green here.

ASSISTANT: Hello, how can I support you?

USER: My plan to visit my friend house is postponed so I want to change my recent reservation.

ASSISTANT: Sure. Just wait a while, I will check the details and get back to you.

USER: Sure.

ASSISTANT: Unfortunately, we did not find any reservation on your given details.

USER: OK, Thank you.

ASSISTANT: Most welcome, have a nice day ahead.