Only the person who made the will, called the testator, can change it. That authority belongs to the testator alone for as long as they are alive and mentally competent, and it cannot be delegated to a spouse, child, attorney, executor, or agent under a power of attorney. Once the testator dies, the document becomes fixed, and the only way to alter its effect is a court challenge on narrow grounds. The question of who can change a will has a short answer and a longer one, because the testator’s freedom runs up against a handful of real limits even during their lifetime.
The Testator Holds Exclusive Authority
A will is treated as one of the most personal legal instruments a person can create, and the law protects that personal character strictly. No one else has standing to modify it, no matter how close the relationship or how strong the opinion about what it should say.
For any change the testator makes to hold up, they must have testamentary capacity at the moment of the change. Every state sets an age requirement, typically 18, and a mental standard: the testator must understand what making or changing a will means, have a general sense of what they own, recognize the people who would naturally inherit from them, and tie those pieces into a coherent plan.1Legal Information Institute. Testamentary Capacity
Courts presume capacity. If a change is later challenged, the person contesting it has to prove the testator lacked competence at the time.
How a Testator Can Change a Will
Adding a Codicil
A codicil is a written supplement that amends an existing will without replacing it.2Legal Information Institute. Codicil It works for targeted changes: naming a different executor, adjusting a single bequest, updating a beneficiary’s information. The codicil should reference the date of the original will and spell out exactly what it changes.
A codicil has to be executed with the same formalities as a will. That means signed by the testator and witnessed by two disinterested people who are not beneficiaries of the change. For anything beyond a minor tweak, most estate planners prefer a fresh will over stacking codicils.
Drafting a New Will
For significant changes, drafting a new will is cleaner. A well-drafted replacement includes a clause expressly revoking all prior wills and codicils, which keeps an outdated version from surfacing during probate.3Legal Information Institute. Revocation of Wills by Instrument A later will can impliedly revoke an earlier one to the extent the provisions conflict, but implied revocation invites litigation. An express clause removes the ambiguity.
After the new will is signed and witnessed, physically destroy the old one. Shredding or tearing it up prevents someone from finding the old copy later and presenting it to the probate court.
Revoking a Will by Physical Act
A testator can revoke a will without drafting any new document. Burning, tearing, or otherwise destroying the will revokes it, but only if the testator acts with the intent to revoke.3Legal Information Institute. Revocation of Wills by Instrument A will that is accidentally lost, stolen, or damaged in a flood is not revoked, because the testator never intended that result.
Partial revocation by physical act is where things get risky. Crossing out a single bequest or scratching through a beneficiary’s name works in some states but not others. States that reject partial revocation by physical act will treat the will as unchanged despite the markings. States that allow it may still require the testator to date and initial each change. Marking up an existing will is one of the most litigation-prone ways to make changes.
The Harmless Error Rule
About a dozen states have adopted a rule based on Uniform Probate Code Section 2-503 that gives courts discretion to honor a will modification even when the strict formalities were not followed. A document can be treated as a valid change if the proponent proves by clear and convincing evidence that the testator intended it to serve that purpose. It can rescue a document that lacked a witness signature or was never formally executed, but it is a safety net, not a plan.
What the Testator Cannot Override
The testator’s authority over their will is broad but not absolute. Several doctrines keep a will from completely cutting out certain people, and one scenario can bind the testator by prior agreement.
A Surviving Spouse’s Elective Share
Nearly every state gives a surviving spouse the right to claim a minimum share of the deceased spouse’s estate regardless of what the will says. The percentage usually falls between roughly one-third and one-half. A testator can write their spouse out entirely, but the surviving spouse can override that by electing their statutory share. Community property states reach a similar result through each spouse’s vested half-interest in marital property. A will cannot be used to fully disinherit a spouse.
Children Born or Adopted After the Will
If a child is born or adopted after the will is signed and the will makes no provision for that child, most states treat the child as a pretermitted heir entitled to a share of the estate as if the testator had died without a will. The protection does not apply if the will makes the omission clearly intentional, or if the testator provided for the child in another way, such as a trust or life insurance.4Legal Information Institute. Pretermitted Heir
Mutual Wills
Married couples sometimes enter a binding agreement to create mutual wills, promising each other that the survivor will not change the will’s terms after the first spouse dies. This goes beyond having matching wills; it requires a contract not to revoke. If the surviving spouse breaks the promise and drafts a new will, a court will not invalidate the new will, but the intended beneficiaries of the original agreement can sue for breach of contract. The typical remedy is a constructive trust imposed on the survivor’s estate for the benefit of those the mutual wills were meant to protect.
Changes That Happen Automatically
Some life events change a will by operation of law, without the testator doing anything.
Divorce
In the vast majority of states, a final divorce decree automatically revokes every provision benefiting the former spouse. Gifts, executor appointments, trustee designations, and powers of appointment granted to the ex-spouse are treated as though the former spouse died before the testator. The same treatment often extends to the former spouse’s relatives. The rest of the will stays in effect, and property that would have gone to the ex-spouse passes as if they had predeceased.
A New Child in the Family
The pretermitted heir rules described above operate the same way: a child born or adopted after the will was signed can automatically take a share, effectively changing the distribution without any action by the testator. Updating the will after a new child arrives is the only reliable way to control the result.
If the Testator Loses Capacity
When a testator becomes mentally incapacitated, no one steps into their shoes to modify the will. A person holding a durable power of attorney can manage finances, pay bills, and in some arrangements make healthcare decisions, but altering the will is outside that authority. The same applies to a court-appointed conservator or guardian.
The law draws this line deliberately. An agent managing someone’s money has obvious opportunities for self-dealing, and allowing will changes would create a serious conflict of interest. A power of attorney also terminates automatically at the principal’s death, at which point the will controls. Any purported amendment made by an agent on behalf of an incapacitated testator is void.
After the Testator Dies
Once the testator dies, the will becomes irrevocable. The executor’s job is to carry out the instructions as written, under the supervision of the probate court. No beneficiary, executor, or family member can amend the terms.
The one path left is a will contest, a lawsuit asking the probate court to invalidate all or part of the will. Only an “interested person” can file one, meaning someone whose financial interest would be affected by the outcome.5Legal Information Institute. Will Contest The common grounds are:
- Lack of capacity: the testator did not meet the mental competency standard when signing.
- Undue influence: someone in a position of trust pressured or manipulated the testator into changes that benefited them.
- Fraud: the testator was deceived about the nature or contents of the document they signed.
- Improper execution: the will was not signed or witnessed in accordance with state law.
A successful contest does not rewrite the will. The court typically falls back on the most recent valid prior will, or distributes the estate under state intestacy laws as if no will existed.5Legal Information Institute. Will Contest
No-Contest Clauses
Many wills include a no-contest clause, also called an in terrorem clause, that strips a challenging beneficiary of their inheritance entirely. These clauses are enforceable in most states, though courts read them strictly. Some jurisdictions recognize a “probable cause” exception, so a beneficiary with a legitimate, evidence-based reason to file is not penalized if the challenge fails.6Legal Information Institute. No-Contest Clause A few states, including Florida, refuse to enforce them at all. Anyone weighing a contest should read the will first; the downside is losing whatever it already provides.
Time Limits
Will contests have deadlines set by state law, and they are unforgiving. The window runs from as little as three months to as long as three years after the will is admitted to probate, depending on the state. Missing it almost always bars the claim permanently, no matter how strong the evidence. Anyone who suspects a will is invalid should talk to a probate attorney as soon as they receive notice that the estate has entered probate.