  Tree level scattering amplitudes in N=4 super Yang-Mills theory are almost,
but not exactly invariant under the free action of the N=4 superconformal
algebra. What causes the non-invariance is the holomorphic anomaly at poles
where external particles become collinear. In this paper we propose a
deformation of the free superconformal representation by contributions which
change the number of external legs. This modified classical representation not
only makes tree amplitudes fully invariant, but it also leads to additional
constraints from symmetry alone mediating between hitherto unrelated
amplitudes. Moreover, in a constructive approach it appears to fully constrain
all tree amplitudes when combined with dual superconformal alias Yangian
symmetry.
