Rolling among G(2) vacua

We consider topology-changing transitions between 7-manifolds of holonomy G (2) constructed as a quotient of CY x S-1 by an antiholomorphic involution. We classify involutions for Complete Intersection CY threefolds, focussing primarily on cases without fixed points. The ordinary conifold transition between CY threefolds descends to a transition between G(2) manifolds, corr esponding in the N = 1 effective theory incorporating the light black hole states either to a change of branch in the scalar potential or to a Higgs m echanism. A simple example of conifold transition with a fixed nodal point is also discussed. As a spin-off, we obtain examples of G(2) manifolds with the same value for the sum of Betti numbers b(2) + b(3), and hence potenti al candidates for mirror manifolds.