What measures should the property management company take to stop the elevator for several hours because of the project quality?

First of all, of course, inform the owner (you can ask the people in the industry Committee to help coordinate) that the elevator is out of order and needs to be shut down for several hours for maintenance. In case the unsuspecting owner is trapped in the elevator.

Second, the emergency notice, the engineering department and the elevator company came to repair. Try to shorten the time.

Third, if you really need to go upstairs and downstairs, the property management company can enthusiastically give corresponding help.