The specification and drawings present a new apparatus such as a lighting fixture and a method for replacing a light engine such as a LED light engine in the lighting fixture by replacing one part carrying the light engine, where the heat sink (e.g., extruded elongated heat sink) can be split into two parts, a replaceable part carrying the light engine and a fixed part. Both heat sink parts may be attached together with a clip to allow the unclipping and replacement of the removable part carrying the light engine. The geometry of the two heat sink parts can be designed in such a way that one part can be attached on top of the other, while providing a predefined alignment and continuous thermal conductivity between the two parts. A space between the two parts can be used to place the clip.