The United Nations Centre for Trade Facilitation and eBusiness UN/CEFACT) standardizes business documents for electronic data interchange. Their approaches towards UN/EDIFACT and XML have later been followed by a conceptual modeling approach called Core components (CC). Having used this approach for four years in practice, it became evident that the support for managing business document models is a prerequisite for successfully utilizing CC. This includes handling variants of business document models on the one hand, and managing the evolution of business document models on the other hand. In this paper we propose an approach to face these challenges by the means of Software Product Line Engineering (SPLE) in combination with dedicated model management operators. The contribution of the approach is twofold. First, SPLE is successfully applied in a new field enabling us to manage variants of business document models. Second, the model management operators support the evolution of business document model variants, whereas the operators defined, contribute to the evolution of product lines as well.