First, if the loan is impaired, the original money should be transferred to the loan impairment person.

Second, the loan value reserve

Third, calculate the loan amortized cost according to the loan impairment-loan impairment reserve.

Fourthly, according to amortized cost's calculation, interest income can be used to offset the loss of loan value, which can be understood as the reduction of loan impairment.

Fifth, if interest is received, writing off loan losses means recovering loan principal.

From the above analysis.

Amortized cost at the end of the period = amortized cost at the beginning+Debit of impairment reserve-Creditor of impairment reserve-actually received interest.

In exchange, see if it's correct.