California Code, Code of Civil Procedure - CCP § 2029.640

If a party to a proceeding pending in a foreign jurisdiction seeks discovery from a witness in this state by properly issued notice or by agreement, it is not necessary for that party to obtain a subpoena under this article to be able to seek relief under Section 2029.600 or 2029.620. The deponent or any other party may also seek relief under Section 2029.600 or 2029.620 in those circumstances, regardless of whether the deponent was subpoenaed under this article.