If you cannot repay the bank loan, you generally cannot request interest-free principal repayment. However, before the repayment period expires, the borrower can negotiate with the bank for installment or deferred repayment. If the bank agrees, the borrower can repay in installments or postpone it; if the bank disagrees, the borrower still needs to repay according to the original time limit and method, and the bank can protect its rights through litigation and other methods.