As Model Driven Architectures (MDAs) gain in popularity, several techniques that test the UML models have been proposed. These techniques aim at early detection and correction of faults to reduce the overall cost of correcting them later in the software life-cycle. Recently, [12, 2] proposed an approach to test the UML design models to check for inconsistencies. They create an aggregate model which merges information from Class Diagrams, Sequence Diagrams and OCL statements, then generate test cases to identify inconsistencies. Since designs change often in the early stages of the software life-cycle, we need a regression testing approach that can be performed on the UML model. By classifying design changes, and then further classifying the test cases, we provide a set of rules about how to reuse part of the existing test cases, and generate new ones to ensure all affected parts of the system are tested adequately. The approach is a safe and efficient selective retest strategy. A case-study is reported to demonstrate the benefits.