Change operators are the building blocks of ontology evolution. Different layers of change operators have been suggested. In this paper, we present a novel approach to deal with ontology evolution, in particular, change representation as a pattern-based layered operator framework. As a result of an empirical study, we identify four different levels of change operators based on the granularity, domain-specificity and abstraction of changes. The first two layers are based on generic structural change operators, whereas the next two layers are domain-specific change patterns. These layers of change patterns capture the real changes in the selected domains. We discuss identification and integration of the different layers with correctness and consistency constraint.