Dismantled (5)
(Other definitions for undid that I've seen before include "Cancelled - destroyed" , "Reversed, destroyed" , "Loosened; ruined" , "Unbuttoned" , "Disentangled" .)
'dismantled' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for took apart that I've seen before include "dismantled" , "Was severely critical" .)
'dismantled' is the definition.
('take down' can be a synonym of 'dismantle')
This is all the clue.
(Other definitions for taken down that I've seen before include "Noted" , "Recorded" .)