If you mean by duty to change or reform that the Church must change her teachings, especially toward modern day "hot-button issues", then that is false. We as people need to change and reform and that includes those who have divorced and remarried without an annulment and those who choose to engage in homosexual activity and those who choose to engage in sex outside of marriage, use contraception, etc. The list includes mostly sexual sins since these are the majority of the issues that many in the Church want her to change.