While such an instrument is legally bindingand allows the donor to claim a deduction, a nonprofit cannot count it at anytime until then proceeds are realized. Nothing is guaranteed to you. It does, however, suggest that your gift officer communicate regularly with the donor as they could one day change that language.
As for language to look for, there is no universal standard. Irrevocable is always a good word to find!
Revocable trusts will often say things like "The grantor may revoke, alter, or amend," or "reserve power to change."
Irrevocable language includes "The grantor expressly waives any right to amend or revoke," or "cannot be altered, modified, or terminated."
John
John Taylor Principal, John H. Taylor Consulting, LLC 919.816.5903 Big ideas; small keyboard