  In this paper, we derive the family switching formula of -n two-sphere fiber
bundle embedded in a smooth four-manifold fiber bundle. In the smooth category,
it is a partial generalization of Fintushel-Stern's argument for
four-manifolds. We also derive an algebraic analogue of the family switching
formula, allowing the P^1 fibration to carry singular fibers. At the end, we
apply the idea of switching to compare the canonical algebraic Kuranishi models
of different classes on the so-called "universal family".
