${\mathrm{KMnO}}_4$ acts as an oxidising agent. In neutral or faintly alkaline medium When alkaline ${\mathrm{KMnO}}_4$ is treated with $\mathrm{KI}$, iodide ion is oxidised to iodate $\left({{\mathrm{IO}}_3}^{-}\right)$ and${\mathrm{KMnO}}_4 \mathrm{is} \mathrm{reduced} \mathrm{to} {\mathrm{MnO}}_2$.  The chemical reaction can be given as,

$2{\mathrm{KMnO}}_4+{\mathrm{H}}_2\mathrm{O}+\mathrm{KI}\to 2{\mathrm{MnO}}_2+2\mathrm{KOH}+{\mathrm{KIO}}_3$

The change in oxidation state of manganese in this reaction is from $+7 \mathrm{to} +4.$