What is the legal test for changing an attorney in a personal injury action?

^14. "[I]n all cases where a party has an attorney in the action or proceeding, the service of papers, when required, must be upon the attorney . . . ." ( 1015.) "A client may of course discharge his attorney at any time [citation], but during the course of a proceeding service of papers on the attorney of record . . . binds the client until the attorney is discharged or substituted out of the case in the manner provided by law." (Reynolds v. Reynolds (1943) 21 Cal.2d 580, 584.) "The attorney in an action . . . may be changed at any time before or after judgment . . . . [] 1. Upon the consent of both client and attorney, filed with the clerk, or entered upon the minutes." ( 284.) "When an attorney is changed . . . written notice of the change and of the substitution of a new attorney . . . must be given to the adverse party. Until then he must recognize the former attorney." ( 285.)