After posting the relevant notice, the residential property set up a community office in the lobby downstairs without the consent of the owner. Is this legal?

It is definitely illegal to say that it is legal. Because simply speaking, the property company is the nanny invited by the owners of the community, including the property houses used by the property company, which are built by the property company with the consent of the owners. In addition to the owner's indoor area, the * * * usable area in the residential area belongs to all owners. The property room of a property company is the same as the nanny room of the rich. If you want to use the location of the downstairs hall mentioned by the landlord, it must be approved by the industry Committee. If there is no industry Committee, it is legal for the property company to use the pool area after two-thirds of the owners agree.