“Each party has the right to amend its pleadings once—without leave of court—within a brief time after its original pleading is filed. The purpose is to facilitate prompt correction of errors or deficiencies in the original pleading. Plaintiffs can amend their complaint once without leave of court before defendant’s answer, demurrer or motion to strike is filed. [The same rule applies to amendment of cross-complaints.]
[California Practice Guide: Civil Procedure Before Trial [citations to primary sources omitted]]
