CA trust law, can a beneficary of a living trust who is on ssi decline their part of money or assign it to another

Note that I am not licensed to practice in your state.

If you do, you will be considered to have accepted the money and then made a gift, either back to the trust or whoever the money went to instead.

If the grantor of the trust is still living, you should talk with them and with an estate planning attorney regarding the consequences of such a trust on your benefits. There are ways to plan around the SSI or SSDI eligibility rules so that you will not be disqualified.

The beneficiary cannot "assign" it to another, but he or she can set up a Special Needs Trust. A Special Needs Trust (SNT) is specifically allowed under federal law. SNT's are designed to allow beneficiaries who are receiving public benefits receive their inheritances, and still remain eligible for public benefits. It is critical to find an estate planning attorney who is knowledgably about First Party Special Needs Trusts. SNT's are very technical, and they have important restrictions on what the beneficiary can do regarding the money.