Cal. Gov. Code § 15865

Whenever the board finds that any portion of the funds in any appropriation for the acquisition of real property under this part is unneeded for the acquisition of the site for which the appropriation was made, the Director of Finance may, upon the recommendation of the board, authorize the transfer of the unneeded funds to any other appropriation for the acquisition of real property made for expenditure under this part and in augmentation of the other appropriation. However, no part of any appropriation made for expenditure pursuant to this part for the acquisition of a site for the use of an institution, college, school, or other agency within a state department shall be transferred to an appropriation for the acquisition of a site for the use of an institution, college, school, or other agency within another state department. For the purposes of this section appropriations for sites for state office buildings, state garages, state warehouses, and official residences are for the use of the Department of General Services.