Reduction of the metal centre in aqueous permanganate ion involves 

In acidic medium, 

${\mathrm{MnO}}_4^{-}⟶{\mathrm{Mn}}^{2+}$

(v.f.$=5$) 

In neutral / basic medium

${\mathrm{MnO}}_4^{-}⟶{\mathrm{MnO}}_2$

(v.f.$=3$)

In strongly basic medium 

${\mathrm{MnO}}_4^{-}⟶{\mathrm{MnO}}_4^{2-}$

(v.f.$=1$)