(1) The claim for which the mortgage exists may be replaced by another claim. The alteration requires the agreement of the creditor and the owner, and registration in the Land Register; the provisions of section 873 (2) and sections 876 and 878 apply accordingly.
(2) If the claim that is to take the place of the previous claim does not belong to the previous mortgage creditor, their approval is required; this approval is to be declared to the Land Registry or to the person in whose favour it is given. The provisions of section 875 (2) and section 876 apply accordingly.