A codicil is a supplement to a previous will that adds to, modifies, amends, or revokes one or more provisions of the earlier will. Laws regarding codicils vary from state to state and in some states a codicil may not replace an earlier will—but in some states it may.
In Iowa, a codicil is recognized as a legal instrument that can be used to make changes to an existing will. The codicil must comply with the same formalities as the original will, which means it must be in writing, signed by the testator (the person making the will), and witnessed by at least two individuals who are present at the same time and who are not beneficiaries of the will. The codicil can add to, subtract from, modify, or revoke provisions of the will. However, it does not replace the original will; instead, it is read in conjunction with the will as part of the overall estate plan. If there are multiple codicils, they are taken in order of their creation unless a later codicil explicitly revokes an earlier one. It is often recommended to create a new will if there are substantial changes to avoid confusion and potential legal challenges.