Legal Question in Wills and Trusts in Washington

Probably only if the trust is 1) irrevocable and 2) funded. If it is not irrevocable, the remainderman may be changed. If the trust is unfunded, it has no 'legal' existence. Only when it is funded or has assets does it actually become a trust recognized by law. One possible exception is a testamentary trust, which is one funded with assets from a last will and testament. There are other less-frequent exceptions, but these are the most obvious and common ones.