KI-I + 3 K2MnVIO4 + 3 H2O KIVO3 + 3 MnIVO2 + 6 KOH

This is an oxidation-reduction (redox) reaction:

3 MnVI + 6 e- 3 MnIV (reduction)

I-I - 6 e- IV (oxidation)

K2MnO4 is an oxidizing agent, KI is a reducing agent.