To do something again or differently, often to correct or improve it. She decided to redo the painting because she wasn't satisfied with the colors.
To redecorate, remodel, or renovate (a room, building, etc.) again. They decided to redo the kitchen with modern cabinets and new lighting.
Computing: to restore a previously undone action, reinstating the document or data to its former state. Press Ctrl+Y to redo the last change you undid.