A lower-mobility parallel manipulator with multiple operation modes can be considered as inherently reconfigurable. 4-RUU parallel manipulator is one such manipulator with three different operation modes. Allowing the first revolute joint axis to have any horizontal orientation leads to a dual reconfigurable 4-rRUU mechanism. This paper presents a novel method to determine its operation modes as functions of the orientation of its base revolute joint axes. Moreover, it's transla-tional workspace is plotted for three mutually perpendicular orientations of its base revolute joint axes. With a goal to realize a working prototype, pareto optimization is used to determine its design parameters such that it has a larger singularity-and interference-free workspace while having a smaller size.