  We solve the partial data Calder\'on problem on conformally transversallly
anisotropic (CTA) manifolds with $L^{n/2}$ potentials - on par with sharp
unique continuation result of \cite{JerKen}. A trivial consequence of this is
the sharp regularity improvement to the result of Kenig-Sj\"ostrand-Uhlmann
\cite{ksu}. This is done by constructing a "Green's function" which possesses
both desirable boundary conditions {\em and} satisfies semiclassical type
estimates in the suitable $L^{p}$ spaces. No Carleman estimates were used in
the writing of this article which makes it starkly different from the
traditional approaches based on \cite{BukUhl} and \cite{ksu}.
