By its terms, California Code of Civil Procedure Section 473 allows a court to grant leave to amend “any pleading.” This broad language, however, is misleading. When a party fails to plead a compulsory cause of action in a cross complaint, a motion for leave to amend should be also brought under California Code of Civil Procedure Section 426.50 rather than just Section 473. While Sections 473 and 426.50 are quite similar, section 473 uses the permissive “may” and provides the court with full discretion in determining whether or not to grant leave to amend, while section 426.50 dictates that the court “shall” grant leave to amend a cross-complaint if the moving party acted in good faith.
As judicial policy strongly favors amendment and California courts “do not exalt form over substance,” it is unlikely that a motion for leave to amend a compulsory cross-complaint will be denied solely because it is brought under section 473 instead of section 426.50. Cal. Code Civ. Proc. § 3528; see also Nestle v. Santa Monica, 6 Cal. 3d 920, 939 (1972) (noting “general rule” of “liberal allowance of amendments”). Nevertheless, best practice mandates recognition of the statutory distinction when bringing motions for leave to amend compulsory cross-complaints.