When sulphur dioxide is passed in an acidified K₂Cr₂O₇ solution,from which range does the oxidation state of sulphur change?

Reaction of sulphur dioxide with K₂Cr₂O₇ in acidic medium is given as
3 SO₂ + Cr₂O₇^2- + 2 H⁺ $\to$3 SO₄^2- + 2 Cr³⁺ + H₂O

Oxidation state of Sulphur in SO₂ is +4 which changes to +6 in SO₄^2-