# Trust Amendment: Definition and How It Works in California

> A trust amendment is a signed document that changes specific terms of an existing trust while leaving the rest in place.

Source: https://ridleylawoffices.com/estate-planning-glossary-california/trust-amendment/

By Eric Ridley, attorney, Ridley Law. Updated September 2026.

A **trust amendment** is a signed document that changes specific terms of an existing trust while leaving the rest of the trust in place. It has to follow whatever method the trust itself sets for making changes.

## How it works in California

See [how a trust amendment compares to a full restatement](https://ridleylawoffices.com/trust-amendment-vs-restatement-california/) for the fuller picture. Under Prob. Code, § 15402, a settlor of a revocable trust modifies it “by the procedure for revocation,” unless the trust instrument says otherwise. That links amendment to the same rules that govern revoking a trust.

Section 15401 sets those rules, and it also sets a limit on them: a trust’s stated method only becomes the exclusive method if the trust instrument “explicitly makes the method of revocation provided in the trust instrument the exclusive method of revocation.” If the trust doesn’t say its method is exclusive, the statutory method stays available alongside whatever the trust describes.

Many revocable trusts spell out their own amendment procedure, such as a signed written amendment delivered to the trustee, and some make that method exclusive. Reading the trust’s own amendment clause first isn’t optional; it controls.

## Why it matters

Getting the method wrong can make an amendment ineffective even when the settlor’s intent is clear. For example, a settlor who sends an email describing a change they want, instead of signing the written amendment their trust requires, may leave that share governed by the trust’s original terms rather than the change they intended.

## Common mistakes

Assuming any signed writing counts as a valid amendment without checking the trust’s own amendment clause. Amending a trust so many times that the current terms are hard to reconstruct from the original document plus a stack of amendments, when a [restatement](https://ridleylawoffices.com/estate-planning-glossary-california/trust-restatement/) would be cleaner. Confusing a trust amendment with a [codicil](https://ridleylawoffices.com/estate-planning-glossary-california/codicil/), which amends a will instead.

## Related terms

- [Trust Restatement](https://ridleylawoffices.com/estate-planning-glossary-california/trust-restatement/): a restatement replaces the entire trust text at once instead of changing individual provisions.
- [Revocable Trust](https://ridleylawoffices.com/estate-planning-glossary-california/revocable-trust/): only a revocable trust’s settlor can generally amend it during their lifetime.
- [Codicil](https://ridleylawoffices.com/estate-planning-glossary-california/codicil/): a codicil is the will equivalent of a trust amendment.
- [Testamentary Capacity](https://ridleylawoffices.com/estate-planning-glossary-california/testamentary-capacity/): capacity questions can arise for a trust amendment much as they do for a will, though the legal standards aren’t identical.

Part of the [California estate planning glossary](https://ridleylawoffices.com/estate-planning-glossary-california/). For the full treatment, see [Trust Amendment vs. Restatement in California: Which Do You Need?](https://ridleylawoffices.com/trust-amendment-vs-restatement-california/) and [Amendment or Restatement? The Right Way to Change Your Trust](https://ridleylawoffices.com/guides/amendment-vs-restatement/).