The Reverse-Spinoff is from what I understand when the amount of activities and assets which normally gets spinned off gets to claim the original name and denomination of the company, while everything else is then transferred under a new umbrella.

Here seems an example regarding Yahoo!

https://venturebeat.com/2015/12/09/yahoo-confirms-its-suspending-its-alibabs-spin-off-plans-will-do-reverse-spin-off-instead/