A Canonical Transformation as a Proposal of the Solution of a Functional EquationStarting with a functional equation of the New Tamm-Dancoff procedure for electronic states of defects in solids we describe an attempt to transform this equation. The aim is to extract a one-particle equation as a projection which is a good approximation for the case of a defect. The transformation usetii s a simple approach to more general canonical transformations leading to inequivalent representations of the many-body problem. It is compared with the elimination procedure given in a first paper [1] which treated the manj-electron problem occuring with the storage of hydrogen in metals