sync problem "instance_change(...)"

my task was to be a drop and pick-up system. For the selection system, I did the following: 1. In the initialization object I specified the object that I want to pick up the object that will replace the selected object in the room 2. When I pick up an object a piece of code is executed:

if global.selectedItem = ":::-=null=-"
{
global.selectedItem = "oTestItem"
ItemSelected = instance_change(oDeletedInstance, true);
gms_instance_sync(ItemSelected, is_full | isc_local, "Selected");
}

but alas, for some reason the change of instance occurs only locally and other players in the room do not see the changes. How can this be fixed?