California Code, Probate Code - PROB § 2501

(a) Except as provided in subdivision (b), court approval is required for a compromise, settlement, extension, renewal, or modification which affects any of the following:

(b) If it is to the advantage of the estate, the guardian or conservator without prior court approval may extend, renew, or modify a lease of real property in either of the following cases:

(c) For the purposes of subdivision (b), if the lease as extended, renewed, or modified gives the lessee the right to extend the term of the lease, the length of the term shall be considered as though the right to extend had been exercised.