California does not provide a standard form for rescinding a power of attorney. However, you may draft your own revocation document.
The revocation should clearly state your intent to rescind the POA and include your full legal name and address, the agent’s name, the date the original POA was signed, the date of revocation and your signature.
To be effective in practice, the agent and any third parties who rely on the POA — such as banks or healthcare providers — must be sent notice of the revocation.