The application of Model Driven Engineering in an industrial context implies working with large models, hence the need for collaborative modeling. Each developer focuses on a part of the large model and may manipulate it independently. As each part evolves rapidly and concurrently due to changes made by different designers, inconsistencies may occur. This work aims to provide support for dealing with concurrent changes. We propose a metamodel for the description of large models, and we also propose a process for the management of concurrent changes.