This ability can change its target's state from "exist" to "not exist" and vice versa. If it cannot be determined if the target actually "exists" or not, it is almost impossible to perform an Event Interference. Since a sudden disappearance of the target would shock those surrounding it, their memories are altered.
Event Interference also allows the user to erase one reality and overwrite it with another (a different world that is a result of an existing possibility). In other words, it imposes a result of a certain phenomenon from a parallel world into the current world. It changes a possibility into reality.
The Takamagahara System used an extortionate amount of Event Interference during the Continuum Shift, using the scattershot event to pick-and-choose which timeline they favored when getting closer to the Blue; this stopped when Hades: Izanami seized control over the AIs.
In BlazBlue: Chronophantasma, Izanami used Event Interference to create conflicts. Amaterasu rewound time to get rid of these conflicts, but it made her closer to the real world, and when she was close enough, she was dragged from the Boundary.
Certain characters are capable of resisting it to some extent, such as those that are outside of the reason, like Valkenhayn R. Hellsing, and to an even greater degree, those that wield the Power of Order, such as Hakumen and Jin Kisaragi. However, it does not include environmental alterations. Hazama also possesses a certain level of resistance, as him being affected is proof that the Master Unit is considerably close.