From Longman Dictionary of Contemporary Englishtake/hand over the reinstake/hand over the reinsCONTROLto take or give someone control over an organization or country Owens will officially take over the reins in a few weeks. → rein
Examples from the Corpus
take/hand over the reins• Campbell Christie takes over the reins at Brockville tomorrow.• The younger generation had taken over the reins.• Finally, on November 24, he took over the reins of the Puzzle Palace from the retiring director. 