Several objects or prestation which are due but may be complied with by the delivery of another object or performance of only 1 of the item; choice may pertain to creditor or even 3rd person

Modes of extinguishing an obligation

It is the designation of debt which is due to which the payment must be applied when 1 and same debtor has several obligation of same kind in favor of 1 and same creditor

The right to designate the debt to which payment shall be applied belongs to creditor

Debt which is the easiest to pay must be settled 1st

1 object due may be complied with by the delivery of another object or performance of another prestation in substitution; choice pertains to debtor

The debtor alienates in favor of the creditor property for the satisfaction of monetary debt

Consigantion can be done prior to tender of payment

It is the gratuitous abandonment by creditor of his rights

Taxes can be the subject of compensation (set off)

Compensation is allowed even if there is a retention or controversy commenced by 3rd persons over either of the debts and communicated in due time to the debtor

It is the changing of object or principal condition

It is effected with consent of creditor at instance of old debtor with the concurrence of new debtor

It is the agreement of parties; intervention and consent of 3 persons: original creditor, new creditor and debtor

If the thing is improved by its nature, or by time, the improvement shall inure to the benefit of the debtor