On the assumption that the person you’re referring to is not just a cooperative a Member of the Executive Committee, and that they act as a letting agent for the Plan and/or maintain the Common Property and/or supervise tradespeople who’ve been sent to the Property by the Strata Manager or by the Executive Committee, then they are indeed classified as a Building Manager or Caretaker who must be appointed by a Motion passed at a General Meeting (simply majority vote) under the specific terms of a formal written Agreement with the Owners Corporation.
The transfer of an Agreement, even in identical terms, to another person or company must also be by way of a Motion passed by way of a simple majority vote at a General Meeting of the Owners Corporation, as must the termination of an Agreement, but only in strict accordance the terms provided in it.
So NO, the appointment of your new Building Manager or Caretaker by the means that you describe was not handled correctly and any Agreement would be therefore void!