Cal. Com. Code § 9207
(b) Except as otherwise provided in subdivision (d), if a secured party has possession of collateral, all of the following apply:
(4) The secured party may use or operate the collateral for any of the following purposes:
(c) Except as otherwise provided in subdivision (d), a secured party having possession of collateral or control of collateral under Section 7106, 9104, 9105, 9105.1, 9106, 9107, or 9107.1 may or shall, as the case may be, do all of the following:
(d) If the secured party is a buyer of accounts, chattel paper, payment intangibles, or promissory notes or a consignor, both of the following apply:
(1) Subdivision (a) does not apply unless the secured party is entitled under an agreement to either of the following: