Persistent source = (Persistent) context.getGraphManager().getNode(nodeId);
if (source != null && source.getPersistenceState() != PersistenceState.HOLLOW) {
Object target = context.localObject((ObjectId) targetNodeId, null);
Property p = propertyForId(nodeId, arcId.toString());
if (p instanceof CollectionProperty) {
((CollectionProperty) p).removeTarget(source, target, false);
}
else {
((SingleObjectArcProperty) p).setTarget(source, null, false);