Short answer. No. Article 2089 makes the security indivisible, so a creditor's heir who has received his share of the debt cannot return the pledge or cancel the mortgage to the prejudice of the other heirs who have not yet been paid. The lien stays intact for all of them until everyone is satisfied.
What the law says
A pledge or mortgage is indivisible, even though the debt may be divided among the successors in interest of the debtor or of the creditor.
Civil Code, Article 2089 — Pledge and Mortgage Are Indivisible. Read the full provision →
What the law says
Neither can the creditor's heir who received his share of the debt return the pledge or cancel the mortgage, to the prejudice of the other heirs who have not been paid.
Civil Code, Article 2089 — Pledge and Mortgage Are Indivisible. Read the full provision →
Indivisibility binds the creditor's side too
The rule that a security cannot be split works against the creditor's heirs just as it does against the debtor's. Article 2089 begins with the general principle — A pledge or mortgage is indivisible, even though the debt may be divided among the successors in interest of the debtor or of the creditor — and then applies it to your situation: Neither can the creditor's heir who received his share of the debt return the pledge or cancel the mortgage, to the prejudice of the other heirs who have not been paid. Receiving your own portion does not entitle you to give up the collateral.
Why you cannot release it alone
The pledge or mortgage secures the whole credit, which has now passed to the co-heirs together. If you returned the pledged thing or cancelled the mortgage once your slice was paid, you would strip the co-heirs who remain unpaid of the security standing behind their shares. Your satisfaction does not shrink the lien or your co-heirs' claim on it. The collateral is common security for the entire outstanding credit, and one heir acting for himself cannot diminish protection that belongs to all of them.
What your position actually is
You hold your share of the credit, and you are of course entitled to have been paid it. But the collateral continues to answer for the balance still owed to the other heirs, and it is discharged only when the entire debt is paid — or, in the special case where several things were each made answerable for a determinate portion of the credit, as those apportioned parts are satisfied. Short of that, the security remains in force, and any cancellation you attempt on your own to the prejudice of the unpaid heirs simply does not take effect against them.
Coordinate rather than act alone
The sensible course is to treat the collateral as shared property of the heirs and to act together. If the debtor wishes to recover his pledged thing or clear his mortgage, he must satisfy all the heirs, not just you — or pay the apportioned portion where the parties provided for one. Do not purport to hand back the pledge or execute a cancellation of the mortgage on your own authority; it will not bind your co-heirs, and it may expose you to them for the prejudice caused. Release comes when the whole credit is paid.