legal ground
Article 695 of the Civil Code in force according to 202 1 1.
Without the written consent of the guarantor, if the creditor and the debtor negotiate to change the contents of the main creditor's rights and debts contract and reduce the debts, the guarantor shall still be responsible 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.
Article 696 of the Civil Code
If the creditor transfers all or part of its creditor's rights without notifying the guarantor, the transfer shall not be effective for the guarantor.
The guarantor and the creditor have agreed to prohibit the assignment of the creditor's rights, and if the creditor assigns the creditor's rights without the written consent of the guarantor, the guarantor is no longer liable to the assignee.