What is the test for establishing an agency relationship?

"`"Agency is the relationship which results from the manifestation of consent by one person to another that the other shall act on his behalf and subject to his control, and consent by the other so to act." [Citation.] "The principal must in some manner indicate that the agent is to act for him, and the agent must act or agree to act on his behalf and subject to his control." [Citation.]' [Citation.] Thus, the `formation of an agency relationship is a bilateral matter. Words or conduct by both principal and agent are necessary to create the relationship . . . .' [Citation.]" (Van't Rood v. County of Santa Clara, supra, 113 Cal.App.4th at p. 571.) An agency relationship may be implied from the conduct of the parties. (Ibid.)

"An actual agent may have either actual or ostensible authority to act for the principal. [Citations.] `Actual authority is such as a principal intentionally confers upon an agent, or intentionally or by want of ordinary care allows the agent to believe himself to possess. [Citation.] Ostensible authority is such as a principal, intentionally or by want of ordinary care, causes or allows a third person to believe the agent to possess. [Citation.] An agent will normally have the authority to do everything necessary or proper and usual in the ordinary course of business for effecting the purpose of his agency. [Citation.]'" (Van't Rood v. County of Santa Clara, supra, 113 Cal.App.4th at p. 572.) "Proof of authority, either actual or ostensible . . . may be established by circumstantial evidence." (Id. at p. 573.)