Complex sentence: She returned to London and was the editor of the UK edition of "Vogue" between 1985 and 1987, and a year later assumed control of the franchise's magazine in New York, reviving what many saw as a stagnating publication.
Split into simpler sentences: She returned to London and was the editor of British "Vogue" between 1985 and 1987. A year she later assumed control of the franchise's magazine in New York, reviving what many saw as a stagnating publication.