((a)) ** General rule** For purposes of this subtitle—

((1)) a real estate investment trust shall not change to any accounting period other than the calendar year, and

((2)) a corporation, trust, or association may not elect to be a real estate investment trust for any taxable year beginning after , unless its accounting period is the calendar year.

((b)) ** Change of accounting period without approval** Notwithstanding section 442, an entity which has not engaged in any active trade or business may change its accounting period to a calendar year without the approval of the Secretary if such change is in connection with an election under section 856(c).