A/R Invoices

I have a dilemma with a client. Company has an a/r account with many outstanding invoices that have been "donated" to a particular client. However, the salesperson has done the donation and the owner has offset all of these "sales" by deducting them from the salesperson's commission to make up the costs. He has manually done that on paper. Taking the commission amount and deducting out the actual a/r invoices and paying him the net. The salesperson is in agreement with this. How do I get rid of all these A/R invoices without affecting past periods? I thought of doing the a/p from a/r clearing  but not sure the steps? Is that a solution to my problem?