24 CFR § 206.134 - Partial release, addition or substitution of security.
(a) A mortgagee shall not release the security or any part thereof, while the mortgage is insured, without the prior consent of the Commissioner.
(b) A mortgagee may, with the prior consent of the Commissioner, accept an addition to, or substitution of, security for the purpose of removing the dwelling to a new lot or replacing the dwelling with a similar or like kind on the existing lot under the following conditions:
(1) The mortgagee obtains a good and valid first lien on the property to which the dwelling is removed or the existing lot upon which the dwelling is rebuilt;
(2) All damages to the structure are repaired or all rebuilding of the structure is completed without cost to FHA; and
(3) The property to which the dwelling is removed or rebuilt is in an area known to be reasonably free from natural hazards or, if in a flood zone, the borrower will insure or reinsure under the National Flood Insurance Program or obtain equivalent private flood insurance coverage, as defined in § 203.16a of this chapter.
(c) A mortgagee may, without the prior consent of the Commissioner, accept an addition to, or substitution of, security for the purpose of removing the dwelling to a new lot under the following conditions:
(1) The dwelling has survived an earthquake or other disaster with little damage, but continued location on the property might be hazardous;
(2) The conditions stated in paragraph (b) of this section exist; and
(3) Immediately following the emergency removal the mortgagee notifies the Commissioner of the reasons for removal.