Smart material based variable internal connectivity has the potential to overcome the inherent conflicting requirements of lightweight shape adaptable structures by reducing the actuation force required for shape adaptation, and, consequently, volume and mass of the actuation system, by increasing the compliance of the structure temporarily. In this paper, we consider shape adaptable sandwich panels with a truss core and implement smart material based variable connections, called mechanical switches, in the trusses of the core. We present three concepts of mechanical switches based on electro-bonded laminates, dielectric elastomer actuators and shape memory alloys, and evaluate their performance in terms of variation in stiffness and in maximum transferable force. Based on these results, we show how the implementation of variable connections in the core trusses can be used to reduce the actuation force by different orders of magnitude for three simple types of deformation of the panel: change in thickness, in transverse shear angle and bending. Further, considering the influence of the mechanical switches on the out-of-plane stiffness of the core, we demonstrate that this approach can be used to obtain changes in thickness of the panel, a kind of deformation that is not possible to obtain with other approaches found in literature. Moreover, we show that mechanical switches can be used to selectively vary the shear stiffness of the panel in the desired direction. Finally, we analyze the limitations of this technology in terms of mechanical properties in order to identify possible applications.