Cal. Gov. Code § 9360.4

The board may require any recipient of a disability allowance under the minimum age for voluntary retirement to undergo medical examination. The examination shall be made by a physician or surgeon, appointed by the board, at the place of residence of the recipient or other place mutually agreed upon. Upon the basis of the examination, the board shall determine whether the physical or mental disability still exists. If the board determines that the recipient is not so incapacitated, his or her disability allowance shall be canceled forthwith.