A method for shaping keratin fibers comprising: providing a crosslinking composition, wherein the crosslinking composition comprises: an active agent, wherein the active agent is a carbonate ester; a cosmetically acceptable carrier; and applying the crosslinking composition to keratin fibers, mechanically shaping the keratin fibers with an appliance at a temperature of from about 50° C. to about 250° C. Also a related composition, use, kit and process.