California Code, Penal Code - PEN § 1033

(a) On motion of the defendant, to another county when it appears that there is a reasonable likelihood that a fair and impartial trial cannot be had in the county. When a change of venue is ordered by the superior court, it shall be for the trial itself. All proceedings before trial shall occur in the county of original venue, except when it is evident that a particular proceeding must be heard by the judge who is to preside over the trial.

(b) On its own motion or on motion of any party, to an adjoining county when it appears as a result of the exhaustion of all of the jury panels called that it will be impossible to secure a jury to try the cause in the county.