What if I want to update or amend my existing will? A codicil is a supplement that allows you to make simple changes to an existing will. We recommend that you consult a solicitor or professional advisor to prepare this. Adding a codicil to your existing will is a simple and easy way to include a gift of a set amount of cash (a Pecuniary Legacy), however, if you are making significant changes, or want to change how the final residue of your estate is divided, it’s advisable to make a new will. Get help with writing or updating your will.