## Generalized Unitarity and Reciprocity Relations for PT-symmetric Scattering Potentials

We derive certain identities satisfied by the left/right-reflection and transmission amplitudes, $$R^{l/r}(k)$$ and $$T(k)$$, of general $${\cal PT}$$-symmetric scattering potentials. We use these identities to give a general proof of the relations, $$|T(-k)|=|T(k)|$$ and $$|R^r(-k)|=|R^l(k)|$$, conjectured in [Z. Ahmed, J. Phys. A 45 (2012) 032004], establish the generalized unitarity relation: $$R^{l/r}(k)R^{l/r}(-k)+|T(k)|^2=1$$, and show that it is a common property of both real and complex $${\cal PT}$$-symmetric potentials. The same holds for $$T(-k)=T(k)^*$$ and $$|R^r(-k)|=|R^l(k)|$$.