Customer receivable account for Bad debt.

Hello all,when a customer invoices are created, the only receivable account hit is always 411****.The requirement is that when a customer don’t pay his invoices for more than 90 days, we are supposed to move the related transactions in another receivable account which started with 416****.As in oracle we are using Dunning report to chase the customers, we were thinking about the system to move the transaction whihc are more than 90 days in the new receivable account 416****, when we run the dunning letters Also, would please let me know as how it will be possible in the system,