The several public entities shall have the authority, as a last resort, to provide replacement housing when a federal-aid project financed in whole or in part with federal aid cannot proceed to actual construction because no comparable replacement sale or rental housing is available. In carrying out the relocation assistance activities, the several public entities shall be authorized to make payments, construct or reconstruct with their own forces, cause to be constructed or reconstructed, and purchase by deed or condemnation any real property for the purposes of providing replacement housing. The acquiring public entity may exchange, lease, or sell to the displaced person such replacement housing. Whenever any real property has been acquired under this Code section and thereafter the acquiring public entity determines that all or any part of such property or any interest therein is no longer needed for such purposes because of changed conditions, the acquiring public entity is authorized to dispose of such property or interest therein in accordance with Code Section 50-16-144.