In neutral or faintly alkaline medium KMnO4 being a powerful oxidant can oxidize, thiosulphate almost quantitatively, to sulphate. In this reaction overall change in oxidation state of manganese will be:

In the reaction of KMnO4 in a neutral or faintly alkaline medium, the manganese (Mn) in KMnO4 is reduced from an oxidation state of +7 to +2.

Here's the step-by-step process:

1. Identify the initial oxidation state of Mn in KMnO4. In KMnO4, Mn is in the +7 oxidation state.

2. Identify the final oxidation state of Mn after the reaction. In a neutral or faintly alkaline medium, KMnO4 is reduced to MnO2, where Mn is in the +2 oxidation state.

3. Calculate the overall change in oxidation state. The change in oxidation state is the final oxidation state minus the initial oxidation state. So, the change is +2 - (+7) = -5.

So, the overall change in the oxidation state of manganese in this reaction is -5.