Provision for doubtful debts

suppose balance sheet for f.y 15-16 close on Dec 2016 and debtor balance reflect Rs 100000 at the end of Dec 2016. now when we come to the month of jan 2017, we know that rs 75000 may be bankrupt. and in the month of feb 2017, we found that the accual bad debt held is rs 25000 only. so pass the entry in the month of jan 2017 and feb 2017.