rewriting schemas

I can't find this in the UBL-NDR-1.0.1, although I seem to remember that it
was there at one point, is there a rule specifically against taking the UBL
schemas and rewriting one of the elements in there to have a different
cardinality, although still within the cardinality of the original schemas
(as one example of a change that would not have any meaningful effect on
validation)?