California Code, Code of Civil Procedure - CCP § 473.5

(a) When service of a summons has not resulted in actual notice to a party in time to defend the action and a default or default judgment has been entered against the party in the action, the party may serve and file a notice of motion to set aside the default or default judgment and for leave to defend the action.  The notice of motion shall be served and filed within a reasonable time, but in no event exceeding the earlier of:  (i) two years after entry of a default judgment against the party;  or (ii) 180 days after service on the party of a written notice that the default or default judgment has been entered.

(b) A notice of motion to set aside a default or default judgment and for leave to defend the action shall designate as the time for making the motion a date prescribed by subdivision (b) of Section 1005, and it shall be accompanied by an affidavit showing under oath that the party's lack of actual notice in time to defend the action was not caused by the party's avoidance of service or inexcusable neglect.  The party shall serve and file with the notice a copy of the answer, motion, or other pleading proposed to be filed in the action.

(c) Upon a finding by the court that the motion was made within the period permitted by subdivision (a) and that the party's lack of actual notice in time to defend the action was not caused by the party's avoidance of service or inexcusable neglect, it may set aside the default or default judgment on whatever terms as may be just and allow the party to defend the action.

(d) This section shall remain in effect only until January 1, 2027, and as of that date is repealed.