Payer/ Deductor must furnish a correction statement if the original return filed is found to be incomplete or inaccurate with regard to TAN, challan details or PAN of the deductee(s). It is nothing but a Revised TDS Return. 

The tax credit will not reflect in the Form 26AS of the payee/deductees in case of errors with the filed TDS returns. Hence payer/deductor is required to fix the error and file the revise return/ correction statement.