California Trust Amendment Form. Utilize our Trust Amendment form to implement modifications to a Revocable Living Trust.To amend a living trust in California, you'll need to create a written amendment document that clearly states the changes you want to make to your trust. A trust amendment form is a legal document you use to make changes to your revocable trust. It isn't meant to change your trust document as a whole. 1. Gather all necessary information regarding the trust and trustees. San Mateo County Certificate of Trust Form. Fill in the blank form formatted to comply with all recording and content requirements. Edit, sign, and share Amendment to Living Trust - California online. No need to install software, just go to DocHub, and sign up instantly and for free.