702.16p

One Aura (Benevolent Blessing) gives the enchanted creature protection from a quality and says the effect doesn’t remove certain permanents that are “already attached to” that creature. This means that, when the protection effect starts to apply, any objects with the stated quality that are already attached to that creature (including the Aura giving that creature protection) will not be put into their owners’ graveyards as a state-based action. Other permanents with the stated quality can’t become attached to the creature. If the creature has other instances of protection from the same quality, those instances affect attached permanents as normal.