California Code, Probate Code - PROB § 6545

Notwithstanding Chapter 2 (commencing with Section 916) of Title 13 of Part 2 of the Code of Civil Procedure, the perfecting of an appeal from an order made under this chapter does not stay proceedings under this chapter or the enforcement of the order appealed from if the person in whose favor the order is made gives an undertaking in double the amount of the payment or payments to be made to that person.  The undertaking shall be conditioned that if the order appealed from is modified or reversed so that the payment or any part thereof to the person proves to have been unwarranted, the payment or part thereof shall, unless deducted from any preliminary or final distribution ordered in favor of the person, be repaid and refunded into the estate within 30 days after the court so orders following the modification or reversal, together with interest and costs.