Machinery used as work equipment often needs to be adapted, extended or modernised during its service life. If a significant modification is carried out in the process, or if a machine is manufactured for the operator’s own use, the operator becomes the manufacturer in legal terms and assumes the obligations set out in the Machinery Regulation (EU) 2023/1230. The presentation focuses on risk assessment as the core of the conformity assessment procedure. Using a practical example, it demonstrates step by step how a piece of work equipment is transformed into a ‘new machine’ through modification or in-house construction, and what requirements the operator, as the manufacturer, must fulfil. From identifying hazards through to risk reduction, technical documentation, the declaration of conformity and CE marking, the necessary steps are explained in a practical manner. Implementation is demonstrated using the Safexpert software tool as an example. Furthermore, the risk assessment is distinguished from the hazard assessment, and their respective roles in the manufacturer’s and operator’s processes are explained. Key topics: Work equipment in transition: modification, retrofitting and self-construction When does the operator become the manufacturer? Substantial modification of machinery Risk assessment in accordance with the Machinery Regulation Step-by-step guide to the conformity assessment procedure From risk assessment to CE marking Practical example using Safexpert