What's the best way to de-gloss walls that were painted with semi-gloss or gloss paint?

to prepare them for re-painting?What's the best way to de-gloss walls that were painted with semi-gloss or gloss paint?
You can use a deglosser or use a primer by zinsser called 123 it made to stick to glossy surfaces without sanding.Just apply a coat of primer and top coat with any paint.Usually with semi gloss you dont need to but gloss would be a good idea so it adheres.What's the best way to de-gloss walls that were painted with semi-gloss or gloss paint?
you need to repaint your walls Just paint over them would be fine
use the lowest grade sand paper there is wet it down. give the walls a quick wet sand. wash and dry.
the paint dept or store will have a product called ';De-glosser';, which is applied and wiped off.