Updated 4 November 2026
CM Law's Ultimate 50 List: Making a Will #36 - What is a codicil, and how is it used to amend a will?
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A new executor, changed family circumstances or a revised gift may mean your will needs attention. A codicil can make changes while keeping the existing will in place. The important question is whether the documents will work clearly together and reflect your wishes when your estate is eventually administered.
What is a codicil?
A codicil is a separate legal document that amends an existing will rather than replacing it. It might change an executor, revise a gift or remove a provision. Your will and effective codicils must be read together to identify the instructions that apply after your death.
The Supreme Court’s probate guidance explains that a codicil can change substantial provisions, not only minor details. Its name does not make it simpler to interpret or exempt it from the requirements applying to testamentary documents.
When might a codicil be suitable?
A codicil may suit a clear, limited change where the rest of your will remains appropriate. Replacing an unavailable executor is one example. The decision depends on the existing wording, earlier amendments and your wider estate plan. A short document is not automatically the cheapest or safest solution.
Ask your solicitor to compare the work involved in a codicil with preparing a fresh will. The assessment should include future administration, because saving drafting time now may create interpretation problems for your executor later.
When is making a new will preferable?
A new will is often preferable where you want several changes, have a complex family situation or already have multiple codicils. It puts your current instructions in one document. Your solicitor should review existing documents before deciding what to revoke and how to preserve any provisions you still need.
The Law Society’s wills guidance recommends considering a fresh will for extensive amendments. My practical advice is to ask someone to explain the complete result back to you; the combined documents should express one coherent plan.
What should I bring to an appointment about changing my will?
Bring your current will, every codicil, a list of proposed changes and information about your family, assets and debts. Include relevant trust deeds, company interests and superannuation nominations. Your solicitor needs the whole picture to assess whether a proposed amendment affects other gifts, appointments or arrangements.
Identify changes since the original will, including deaths, relationship changes and significant asset sales. Explain your intended outcome in ordinary language before suggesting replacement wording. Tell your solicitor if an original document is missing or held elsewhere.
How should a codicil identify the changes?
A codicil should clearly identify the will being amended and specify which provisions are replaced, removed or added. It should address earlier codicils where necessary and confirm the provisions intended to continue. Ambiguous references or inconsistent gifts can make your executor’s task difficult and invite disputes about your intentions.
Check names, dates, substitute beneficiaries and the clause dealing with the remainder of your estate. Changing one gift may alter what is available for others. Avoid relying on a generic template without checking how it interacts with your existing wording.
How must a codicil be signed and witnessed in NSW?
A codicil ordinarily requires the same execution formalities as a will. It must be written, signed by you or at your direction in your presence, with your signature made or acknowledged before two witnesses present together. At least two witnesses must then sign in your presence.
The State Library’s guide to valid wills explains these requirements. Date the document and arrange proper execution. If disability, language needs or remote witnessing affect the process, obtain advice before signing so the appropriate procedure and evidence are in place.
Can a beneficiary witness my codicil?
Use independent witnesses who do not receive gifts under the testamentary documents. In NSW, a gift to an interested witness may be void, subject to statutory exceptions. That does not automatically invalidate the entire will or codicil. Avoid creating a problem that later requires consent, evidence or a court decision.
Section 10 of the Succession Act addresses interested witnesses. The Court’s complex probate guidance explains the potential consequences. Have your solicitor check witness suitability, including any interaction between gifts in the original will and the proposed codicil.
Can I simply write changes on my existing will?
Do not assume handwritten edits, crossed-out gifts, an email or an unsigned draft will validly amend your will. Alterations have their own legal requirements. A court can sometimes recognise an informal testamentary document under section 8, but that requires evidence and a judicial decision rather than automatic acceptance.
Official probate guidance on informal documents explains the additional process. Preserve any existing material and obtain advice before adding further marks, removing pages or destroying documents. A properly prepared codicil or replacement will usually provides a clearer route.
What if there are concerns about capacity or pressure?
You must have the capacity required to make the codicil and understand and approve its contents. Age, illness or a diagnosis does not answer that question by itself. The proposed changes and your understanding at the relevant time matter. Your instructions must also be freely given, without improper pressure.
A solicitor may speak with you privately, record detailed instructions and seek a suitable medical assessment where concerns arise. The Law Society’s capacity guidance supports careful evidence gathering. Family members should explain practical concerns without substituting their wishes for yours.
Can my attorney or guardian amend my will for me?
No. Appointing an attorney or enduring guardian does not authorise that person to make a codicil for you. You may still change your own will if you retain the necessary capacity. Where capacity is absent, the Supreme Court has a separate statutory will jurisdiction with safeguards and evidentiary requirements.
Legal Aid NSW explains the distinction. A power of attorney concerns authority during your lifetime; it is not a replacement for testamentary instructions. Seek advice promptly if deteriorating health creates urgency, while allowing proper assessment and independent instructions.
Should marriage, separation or divorce trigger a review?
Yes. Marriage can revoke an earlier will, subject to statutory exceptions, while divorce generally affects gifts and appointments benefiting a former spouse. Separation alone does not revoke your will. These events require a review of the existing document’s legal status, not an assumption that adding one clause fixes everything.
Other useful review points include a beneficiary’s death, new children and changes in dependency. Legal Aid’s updating guidance explains common triggers. Tell your solicitor the dates of relevant events and whether an earlier will anticipated a particular marriage.
Can a codicil control all my assets?
No. A codicil changes your will, but your will does not necessarily control everything connected with your finances. Jointly held assets, superannuation, trust property and assets owned by a company require separate examination. The ownership structure and applicable rules determine what can actually pass through your estate.
NSW Government guidance on wills explains these boundaries. Coordinate nominations, trust succession and company arrangements where appropriate. Listing an asset in a codicil does not itself transfer ownership or override a binding arrangement outside the estate.
What does a real NSW codicil dispute show?
Mackinlay v Holliday [2023] NSWSC 949 shows why evidence of understanding matters when a codicil is challenged. The deceased’s son disputed a 2018 codicil on testamentary capacity and knowledge-and-approval grounds. The Supreme Court upheld it, finding the necessary capacity and approval despite evidence of cognitive impairment.
The codicil changed the executor from the deceased’s wife and son to his accountant, altered the wife’s gift to a life interest and changed other provisions. Justice Darke examined medical and lay evidence, instructions, correspondence and discussions about the changes. The Court granted probate of the 2007 will together with the codicil and dismissed the son’s claim. In the later costs decision, the son was ordered to pay half the accountant’s costs, excluding the costs application. This was a decision on the particular evidence, not a rule that cognitive impairment makes every amendment valid or invalid.
How should I store the codicil and tell my executor?
Keep the original codicil securely with the original will and any other operative codicils, and tell your executor where they are held. Keep accessible copies clearly identified as copies. The executor needs the complete set of documents, because probate of an amended will ordinarily involves both the will and codicils.
The Court’s application guidance requires the originals to be filed when seeking probate. Avoid marking, dismantling or attaching new material to signed documents. Review storage arrangements if you move, change solicitors or change your executor.
How can CM Lawyers help me update my will?
CM Lawyers can review your existing documents, discuss your intended changes and advise whether a codicil or a new will better suits your circumstances. We can also consider execution, capacity evidence, storage and related estate planning arrangements, so the change fits the plan your executor will eventually need to follow.
Arrange a will review with CM Lawyers on 02 9557 9000 or at lawyers@cmlaw.com.au. Our office is Level 3, Unit 3.07, 18–30 Faversham Street, Marrickville NSW 2204.
General information only, current at 4 November 2026. This article is not legal advice for your circumstances.
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