Stop replicating a subobject and tell actor channels who spawned a replica of this subobject to release ownership over it. This means that on the remote connection the network engine will stop holding a reference to the subobject and it's up to other systems to keep that reference active or the subobject will get garbage collected. If you are using the legacy subobject replication method (ReplicateSubObjects() aka bReplicateUsingRegisteredSubObjectList=false) make sure the subobject doesn't get replicated there either.