Section 34(2)(a) in The West Bengal Panchayat Elections Act, 2003
(a)unless otherwise directed by the Commission and for reasons to be recorded in writing, be revised, wholly or in part, with reference to the qualifying date referred to in sub-section (1) -(i)before each general election to any Panchayat, and(ii)before each by-election to fill a casual vacancy in a seat allotted to the constituency, and