Please share this suggested wording with your legal advisor.
I give to Population Connection, a Washington DC non-profit (Tax ID #94-1703155), or its successor, the sum of $___________________, for any purpose as Population Connection deems appropriate.
I give to Population Connection, a Washington DC non-profit (Tax ID #94-1703155), or its successor (the real estate located at __________________ or 1000 shares of XYZ stock), for any purpose as Population Connection deems appropriate.
I give to Population Connection, a Washington DC non-profit (Tax ID #94-1703155), or its successor, ________% of the rest of my estate, for any purpose as Population Connection deems appropriate.