CA Civ Code Section 2845

A surety may require the creditor, subject to Section 996.440 of the Code of Civil Procedure, to proceed against the principal, or to pursue any other remedy in the creditor’s power which the surety cannot pursue, and which would lighten the surety’s burden; and if the creditor neglects to do so, the surety is exonerated to the extent to which the surety is thereby prejudiced.