carte blanche
From Longman Dictionary of Contemporary Englishcarte blanchecarte blanche /ˌkɑːt ˈblɑːnʃ $ ˌkɑːrt-/ noun [uncountable] LET/ALLOWpermission or freedom to do whatever you want The new manager will be given carte blanche as long as she can increase the company’s profits. She had carte blanche to produce a film suitable for children.Examples from the Corpusgiven carte blanche• The director was given carte blanche to make his epic movie.Origin carte blanche (1700-1800) French “white card, document with no writing”