Balance the redox reaction

KMNO4 + NH3 - --> KNO3 + MNO2 + KOH + H2O

To balance the redox equation in the ion-electron method (also called the half-reaction method), the redox equation is separated into two half-equations - one for oxidation and one for reduction. Each of these half-reactions are balanced separately by the number of electrons which accepted by reduction or donated by oxidation and then combined to give the balanced redox equation.