$session->removeElement_P( $object, $relation, [ $type, $value ] )
The removeElement_P() function removes an element from an object relationship, such as ComposedOf.
In order to access the low-level primitive version of this call, invoke it by using the primitive method because the InCharge::session module has a method of the same name that provides an enhanced interface.
$session->removeElement_P("Router::gw", "ComposedOf", [ "OBJREG", "Host::pingu6" ] );