Optimistic version control systems enable globally distributed teams of developers to work together asynchronously. Every developer works on a local copy and consequently, no developer is ever detracted from working by waiting for a resource. The price for this flexibility is payed at the moment when conflicting modifications must be integrated into one consolidated version. In this paper, we discuss conflicts and their need for resolution in the context of model versioning and provide the basic concepts necessary to build a model versioning system which guides modelers through the critical consolidation phase by recommending suitable patterns.