Hi
no need for a program;
1. If these are positive and negative values in simply create 2 new
columns and in the first cell of the first column type the formula
= -"A2"

where I have assumed the first number in your two Opening Balance and
Pending Balance columns is in "A2". Now copy this formula to the first
cell in the second new column, then select all of the two columns and
do Edit, Fill Down.

2. If these are two columns of TEXT with "+" and "-" at the start of
each number do the same as 1 but use the formula
=IF(LEFT(A2,1) = "+",REPLACE(A2,1,1,"-"),IF(LEFT(A2,1) =
"-",REPLACE(A2,1,1,"+")))


regards
Paul