Such effects change the original DP shown on the target card to the predetermined value shown in the effect. For example, if a Digimon has an original DP of 8000 and it's chosen as the target for a "[Main] Change the original DP of 1 of your opponent's Digimon to 3000 until the end of their turn" effect, that Digimon's original DP will become 3000 instead of 8000.