I think the idea is to re-cast and replace some of the actors either totally or by employing new voice talent coupled with editing.

For example Jar-Jar in theory could be replaced both physically and vocally, either by a human in an alien/droid suit or by another human character.

Anakin could still have the face of Hayden but do things differently on screen and have the voice of an actual human being with emotions.

Entirely new characters could be added to the movies to either replace hideous CGI cartoons or to deliver information that alters or adds to the plot.

Others could be removed from scenes where it makes no sense them being there.

For example if Fett is to be the template for the Clones it would make sense to remove him from Dooku's side as it's bloody obvious that the Jedi are being set up.