Haven't you read anything that has been posted about this above???
Don't bother with Google, go to the Vatican's site and get it straight from the horse's mouth. Unitatis Redintegratio n.6:
"Thus if, in various times and circumstances, there have been deficiencies in moral conduct or in church discipline, or EVEN IN THE WAY THAT CHURCH TEACHING HAS BEEN FORMULATED..."
The link is here:
http://www.vatican.va/archive/hist_councils/ii_vatican_council/documents/vat-ii_decree_19641121_unitatis-redintegratio_en.html