Mo. Rev. Stat. § 473.437: Extension or renewal of encumbrances of assets.

When any assets of the estate are encumbered by mortgage, pledge or other lien, the personal representative may renew or extend any obligation secured by the encumbrance or convey or transfer the assets to the creditor in satisfaction of his lien, in whole or in part, pursuant to agreement with the holder of the encumbrance, whether or not the holder of the encumbrance has filed a claim, if it appears to be for the best interest of the estate.