The United Nations Centre for Trade Facilitation and Electronic Commerce provides a conceptual approach named Core Components for defining business document models based on reusable building blocks. For the application in concrete business scenarios, these building blocks need customizing, resulting in different variants of business document models. In previous work we have proven the application of concepts from Model-Driven Product Line Engineering to manage the resulting business document model variants. However, due to the highly dynamic environment of electronic commerce with ever-changing market requirements, business document models evolve over time. This adds another dimension of variability to the problem domain leading to complex evolution scenarios. In this paper, we define evolution patterns for capturing the different types of evolution present in the context of business document model variants. Having such patterns at hand, makes the different types of evolution in business document models more tangible.