P.R. Laws tit. 30, § 2608
A recorded mortgage may be exchanged for another of lower rank or postponed for another to be constituted in the future in accordance with the following requirements:
First.— That the creditor who is exchanging or is going to postpone expressly consents to the exchange or postponement in a public document.
Second.— That the exchange or postponement has the consent of future or intermediate creditors who appear in the Registry. In the event of an exchange or postponement, the holders of liens on the postponed or exchanged mortgage must always give their consent.
Third.— That when a future mortgage is converted into one of higher rank, the maximum liability as to capital, interest costs or other concepts must be determined, as well as its maximum duration.
Fourth.— That the mortgage that is to have preference, whether it be a future mortgage or one granted simultaneously, be recorded within the term necessarily agreed upon to such effect, which must not exceed four years.
After the expiration of the term indicated in number four, if the new mortgage has not been recorded the right to postponement shall expire.
The recording of a postponement in favor of a future mortgage shall only affect third persons acquiring the postponed mortgage.
History —Mortgage Law, 1979, § 189.