  Exclusive $\pi^o$ electroproduction from nucleons was first suggested by
Ahmad, Goldstein and Liuti for extracting from experimental data the tensor
charge, transversity and other quantities related to chiral odd combinations of
generalized parton distributions. We now explain the details of the process:
{\it i)} the connection between the helicity description and the cartesian
basis; {\it ii)} the dependence on the momentum transfer squared, $Q^2$, and
{\it iii)} the angular momentum, parity, and charge conjugation constraints
($J^{PC}$ quantum numbers).
