CalHFA only allows resubordination if the borrower is part of their servicer's loss mitigation program:

https://www.calhfa.ca.gov/homeownership/programs/refi.htm

There is also one resubordination allowed of the Dream For All Shared Appreciation loan:

https://www.calhfa.ca.gov/homeownership/programs/policy-resubordination-cadfa.pdf