Legal basis: Civil Code of People's Republic of China (PRC).
Article 692 The suretyship period is the period during which the surety assumes the suretyship responsibility, and may not be suspended, interrupted or extended. The creditor and the guarantor may agree on a guarantee period, but if the agreed guarantee period expires before or at the same time as the performance period of the principal debt, it is deemed that there is no agreement; If there is no agreement or the agreement is unclear, the guarantee period shall be six months from the date of expiration of the main debt performance period. Where the creditor and the debtor have not agreed or clearly agreed on the time limit for the performance of the principal debt, the guarantee period shall be counted from the date when the grace period for the creditor to request the debtor to perform the debt expires.
Article 695 Where, without the written consent of the guarantor, the creditor and the debtor negotiate to change the contents of the principal creditor's rights and debts contract or reduce the debts, the guarantor shall still be liable for the changed debts; Where the debt is aggravated, the guarantor shall not be liable for the aggravated part. Without the written consent of the guarantor, if the creditor and the debtor change the performance period of the principal creditor's rights and debts contract, the guarantee period will not be affected.