Don’t know about NSW. In the ACT, our strata act says the committee chair is also the chair of the AGM unless unable or unwilling to do it, in which case the AGM has to elect a chair for the meeting. Without having read the NSW legislation, I would assume the old executive remains the executive until the AGM has conducted the election of the new committee. Once the result of the election is declared by the chair of the AGM, the new committee is the executive, except that the old chair would continue to chair until the end of the AGM.