legal ground
Article 55 1 of the Civil Code
Where the debtor transfers all or part of its debts to a third party, it shall obtain the consent of the creditor. The debtor or a third party may urge the creditor to give consent within a reasonable time. If the creditor fails to express it, it shall be deemed as disagreement.
Article 553
If the debtor transfers the debt, the new debtor may claim the defense of the original debtor against the creditor; Where the original debtor enjoys the creditor's rights, the new debtor may not claim offset from the creditor.
Article 554 Where the debtor transfers the debt, the new debtor shall bear the subordinate debt related to the main debt, except that the subordinate debt belongs exclusively to the original debtor.