Hi Mahesh,
This is possible in two ways.
(1) You can use substitution thru GBB1 transaction code. here you can validate Transaction code, order type and GL it is matches then replace GL with new GL, but here problem is if there are more GL to replace we have to write so many rules, I will prefer this if GL are not more than 5.
and
(2) You can use exit in finance entry and replace GL after validating the required data.
Hope you will understand it.
Raj