One word for "put something to a lower form/level/grade"
Solution 1:
You could consider using the verb degrade which means:
Lower the character or quality of
[Oxford Online Dictionary]
Slavery was a known practice which was used in the world to degrade human beings to the level of commodity and animals.
[The Historian 2007]
Solution 2:
"Demote" might be appropriate.
Move (someone) to a lower position or rank, usually as a punishment: ‘the head of the army was demoted to deputy defence secretary’.
(Oxford On-Line Dictionary) http://www.oxforddictionaries.com/definition/english/demote