Simplify the following text for a Grade 12 native English-speaking person.
Original: They are also kept under guard at night by Buzz ( Tim Allen ) whom Lotso has reverted to a demonstration state to destroy his memories , restoring his original `` Space Ranger '' persona and allying with him .
Simplified: They are also kept under guard at night by Buzz whom Lotso has reverted to demonstration mode , restoring his original `` Space Ranger '' persona and allying with him .