Detailed Answer — How to create a new will that automatically revokes your prior will under California law

This section explains, in plain language, how to update your will so the new document replaces the old one without filing either document with the court. It outlines the legal rules in California, step-by-step actions you can take, and the risks to watch for.

Key California law that controls revocation

Revocation by a later will or codicil: California law treats a later will or codicil that revokes or is inconsistent with an earlier will as revoking the earlier will. See California Probate Code §6122: Prob. Code § 6122.
Revocation by physical act: A will can also be revoked by destroying (burning, tearing, canceling, obliterating, or other destruction) the will with the intent to revoke. See California Probate Code §6123: Prob. Code § 6123.
Execution formalities for new wills: For a new (attested) will, you must follow the formal signing and witnessing rules. See California Probate Code §6110 for execution requirements and §6111 for holographic (handwritten) wills: Prob. Code § 6110, Prob. Code § 6111.

Short answer

Create and properly execute a new will (or codicil) that contains an express clause revoking all prior wills or codicils. The new properly executed will automatically revokes earlier wills under California Probate Code §6122. You do not have to file either document with the court during your lifetime; wills are generally filed only at death.

Practical step-by-step process

Decide whether you need a full new will or a codicil.
A codicil is suitable for a small change (a new executor, a different small bequest). A full new will is usually clearer when you make multiple or substantial changes. Both must meet execution formalities to be effective.
Include an express revocation clause.
Put clear language near the start of the new document saying it revokes all prior wills and codicils. Simple sample wording people use: “I hereby revoke all prior wills and codicils.” That explicit language makes the testator’s intent clear and avoids ambiguity under Prob. Code §6122.
Execute the new document correctly.
If you use an attested (typed) will, sign it in the presence of two qualified witnesses who then sign, following the rules in Prob. Code §6110. If you make a handwritten (holographic) will, it must be entirely in your handwriting and signed by you to be valid under Prob. Code §6111. Failure to follow formalities can invalidate the new document and leave the old one in effect.
Destroy the earlier original will if possible (optional but strong evidence).
If you have the original prior will, physically destroying it (burn, tear, etc.) with the intent to revoke is another clear method of revocation under Prob. Code §6123. If you destroy it yourself, keep a note of what you did. If you cannot retrieve the prior original, an expressly revoking later will still revokes the earlier will by operation of law.
Keep the original of the new will safe and tell someone where it is.
Do not file the will with the court while you are alive. Instead, keep the original in a secure place (safe deposit box, attorney’s file, home safe) and tell your executor/trusted person how to find it. At death the executor typically files the will with the probate court as part of opening probate.

Common situations and how they are handled

New will conflicts with a prior typed will: The new properly executed will controls as to inconsistent provisions and revokes the earlier will in whole or in part (Prob. Code §6122).
New handwritten will revokes a typed will: A valid holographic will can revoke a prior attested will if it meets handwriting/signature rules and expresses intent to revoke.
Destroyed prior will: Physical destruction of the old will with intent to revoke is effective (Prob. Code §6123), but destruction alone can be disputed if others claim lack of intent. Combining express revocation language in the new will with destruction of the old original is the most robust approach.
Joint or mutual wills: Wills that are part of a contract (mutual wills) or joint wills can have special rules. A new will might not be able to revoke certain contractual obligations—consult an attorney if you have a joint or mutual will situation.

What you should avoid

Don’t make handwritten changes (scratching out or adding words) on an executed attested will without following formalities—this can cause disputes.
Don’t rely on informal notes or a “draft” typed will signed without witnesses; unsigned or improperly signed instruments can be invalid.
Avoid using unclear language—be direct: an express revocation clause removes doubt.

When to consult an attorney

Get legal advice if you have any of these complicating factors: beneficiaries with competing claims, blended families, prior agreements about wills, large trusts or estate tax planning, incapacity issues, or if you are unsure whether your new document meets California execution rules. A lawyer can prepare a clean new will, add witness supervision, and store the original securely.

Helpful Hints — Practical tips for replacing an old will in California

Include an explicit revocation clause in the new will: “I revoke all prior wills and codicils.”
Follow execution rules exactly: for attested wills, sign with two witnesses present (Prob. Code §6110).
If using a holographic will, ensure it is entirely in your handwriting and signed (Prob. Code §6111).
If possible, retrieve and destroy the original old will to provide strong proof of revocation (Prob. Code §6123).
Keep the new original will in a safe place and tell your executor/trusted person where it is stored.
For small changes, consider a codicil rather than rewriting the entire will; it must be executed with the same formalities.
Be cautious with joint/mutual wills or property held in trust—these can affect whether the new will can fully revoke prior arrangements.
Maintain clear records: date the new will and keep a copy of the executed document for your records (but keep the original safe).

Important reminder: This article explains California law but does not provide legal advice. It is not a substitute for consulting a licensed attorney about your specific situation. If you have questions about how a new will will affect property distribution, spousal rights, or tax/planning issues in California, talk to an estate planning attorney.