Why identProps doesn't identify the relationship in apoc.merge.relationship

Hi! By using apoc.merge.relationship() function I expect that relationships should be identified only by identProps argument. So for Example if I update the relationshipType but provide same identProps I want to update the name of relationship and not create another one with same identProps. Since relationship constraints are part of enterprise addition I can't have unique relationships. The question is how can I create/update relationships identifying them only by there id and not type. Thanks in advance!