1. A computer method for model transformation reapply, comprising the steps of: through a programming model transformation, generating a target model having one or more model elements; marking parts of the target model as non-changeable by inserting into the generated target model respective annotations to the model elements indicating which parts are non-changeable and thus preservable; and reapplying the programming model transformation to make changes to the target model but preserving manual changes made to the model elements based on the inserted annotations.