  The model-independent parametrization for exclusive hadronic form factors
commonly used for semileptonic decays is generalized to allow for the inclusion
of above-threshold resonant poles of known mass and width. We discuss the
interpretation of such poles, particularly with respect to the analytic
structure of the relevant two-point Green's function in which they reside.
Their presence has a remarkably small effect on the parametrization, as we show
explicitly for the case of $D \to \pi e^+ \nu_e$.
