Let me give an intuitive example.
Socrates is a being. During his life-time he goes through several stages (intrinsic states): he grows older and that implies some bodily changes from infant to greybeard. But he also comes from time to time under the influence of external agents that can accidentally cause changes in him, for instance his skin can be temporarily tanned, because it happened to be a sunny summer (extrinsic state). But despite of all these changes, he remains Socrates, his Essence remains the same.