If, upon proceeding to canvass the votes, it clearly appears to the clerk and his assistant that in any statement produced to them certain matters are omitted which should have been inserted or that any mistakes which are merely clerical exist, they shall cause the statement to be sent to the precinct judges from whom they were received to have the same corrected. The judges of election, when so demanded, shall make such correction as the facts of the case require but shall not change or alter any decision made before by them. The clerk and his assistant may adjourn from day to day for the purpose of obtaining and receiving such statement.