If you already have an existing will, it is simple for you and your attorney to amend the document by writing a codicil.  The following language may help you and your attorney when amending your bequest.

I give, devise, and bequeath $ ___________ to Texas Pride Impact Funds, a Texas nonprofit corporation EIN #123456789, for its charitable uses and purposes.

In all other respects I ratify and confirm all of the provision of my said last Will and Testament dated on the _________ day of ______________, 20_ _

IN WITNESS WHEREOF, I sign, publish and declare this instrument to be a Codicil to my last Will and Testament in the presence of the persons witnessing said Codicil at my request this _____ day of ___________, 202_ _

You should consult with your attorney on the proper way to execute a codicil in Texas.  Generally, a codicil requires you to sign with two witnesses to your signature.  A best-practice is to have the codicil notarized to simplify probate.