A revert puts back what the change wrote. It will not write over a value that has changed since.
Conflict
Before a revert, the app reads each value again. If your store no longer holds the value the change wrote, someone or something has changed it since: you, in the admin; a colleague; another app. That value is marked Conflict in the preview and Left as it is in the result.
The revert goes ahead for every other value.
What to do about it
Open the row in the grid, see what it holds now, and type the value you want. Apply that as a new change.
Nothing to put back
If every value is a conflict, Revert N values is off. Nothing is written.
A change reverted twice
A change's page still offers Revert these changes after a revert. The preview then reads the store, finds each value already put back, lists it as a Conflict, and leaves Revert N values off.