A product line is an approach for systematically managing configuration options of customizable systems, usually by means of features. Products are generated by utilizing configurations consisting of selected features. Product-line evolution can lead to unintended changes to product behavior. We illustrate that updating configurations after product-line evolution requires decisions of both, domain engineers responsible for product-line evolution as well as application engineers responsible for configurations. The challenge is that domain and application engineers might not be able to talk to each other. We propose a formal foundation and a methodology that enables domain engineers to guide application engineers through configuration evolution by sharing knowledge on product-line evolution and by defining configuration update operations. As an effect, we enable knowledge transfer between those engineers without the need to talk to each other. We evaluate our method by providing formal proofs that show product behavior of configurations can be preserved for typical evolution scenarios.