period established by the applicable housing credit agency (not to exceed 25 months from the date on which the casualty loss arises). The determination under paragraph (1) shall not be made with respect to a property the basis of which is affected by a casualty loss until the period described in the preceding sentence with respect to such property has expired. . (b) Effective date The amendment made by this section shall apply to casualty losses arising after the date of the enactment of this Act. 303. Modification of rights relating to building purchase (a) In general Subparagraph (A) of section 42(i)(7) of the Internal Revenue Code of 1986 is amended— (1) by striking a right of 1st refusal and inserting an option , and (2) by striking the property and inserting the property or a partnership interest relating to the property . (b) Conforming amendment Subparagraph (B) of section 42(i)(7) of the Internal Revenue Code of 1986 is amended by adding at the end the following new sentence: In the case of a purchase of a partnership interest, the minimum purchase price is an amount equal to such interest's ratable share of the amount determined under the first sentence of this subparagraph. . (c) Effective date The amendments made by this section shall apply to agreements entered into or amended after the date of the enactment of this Act. 304. Modification of 10-year rule