  It is recently conjectured that generic non-extremal Kerr black hole could be
holographically dual to a hidden conformal field theory in two dimensions.
Moreover, it is known that there are two CFT duals (pictures) to describe the
charged rotating black holes which correspond to angular momentum $J$ and
electric charge $Q$ of the black hole. Furthermore these two pictures can be
incorporated by the CFT duals (general picture) that are generated by
$SL(2,\mathbb{Z})$ modular group. The general conformal structure can be
revealed by looking at charged scalar wave equation in some appropriate values
of frequency and charge. In this regard, we consider the wave equation of a
charged massless scalar field in background of Kerr-Sen black hole and show in
the "near region", the wave equation can be reproduced by the Casimir operator
of a local $SL(2,\mathbb{R})_L \times SL(2,\mathbb{R})_R$ hidden conformal
symmetry. We can find the exact agreement between macroscopic and microscopic
physical quantities like entropy and absorption cross section of scalars for
Kerr-Sen black hole. We then find an extension of vector fields that in turn
yields an extended local family of $SL(2,\mathbb{R})_L \times
SL(2,\mathbb{R})_R$ hidden conformal symmetries, parameterized by one
parameter. For some special values of the parameter, we find a copy of
$SL(2,\mathbb{R})$ hidden conformal algebra for the charged
Gibbons-Maeda-Garfinkle-Horowitz-Strominger black hole in the strong deflection
limit.
