It's understandable that you have had trouble finding information. The 1997 revision of Louisiana succession law, which took effect in 1999, does not contain the word "codicil." The information you need is contained in the Louisiana Civil Code, which can be accessed through the Louisiana Legislature website. Civil Code Article 1608 deals with the revocation of a legacy or other testamentary provision, and Civil Code Article 1610 deals with any other modification of a testament (will). Both require modifications to be in one of the forms required for testaments. Civil Code Article 1575 provides the requirements for an olographic testament: "An olographic testament is one entirely written, dated, and signed in the handwriting of the testator." The signature must be at the end of the document, but the court may, in its discretion, may consider anything written after the signature.