Digital-first execs in industries from accounting to transportation recognize that software is critical to platform business models. Beyond delivering the immediate customer value these leaders envision, enterprise architecture (EA) pros can meet a platform business need that execs are likely to miss: Software architecture determines how well a platform business can adapt to the inevitable twists, turns, and surprises it will face. This report outlines four steps for building a platform business with a software architecture to enable disruptive change.