Some people assume preservation means freezing a building in time, but many property owners know that restoring a building often requires making changes. This can mean replacing a missing detail, building an addition, or retrofitting for energy conservation. These, and other changes, are essential in maintaining our historic districts and for keeping historic buildings in active service. The key is to make these changes while preserving those features that contribute to a property’s significance. How can property owners make design decisions that will meet new functional needs and preserve our historic properties?  Noré Winter, a principal with Winter & Company, Boulder, Colorado asks that we refocus the definition of “preservation,” and provides case studies for what that means.