CA Evid Code Section 777

(a)

Subject to subdivisions (b) and (c), the court may exclude from the courtroom any witness not at the time under examination so that such witness cannot hear the testimony of other witnesses.

(b)

A party to the action cannot be excluded under this section.

(c)

If a person other than a natural person is a party to the action, an officer or employee designated by its attorney is entitled to be present.