Complex sentence: Chance's stage and musical persona were finalized by romantic partner and agent Anya Philips, whose death from cancer in 1981 coincided with Chance's withdrawal from public visibility for over a decade, before reappearing in the mid- 1990s.
Split into simpler sentences: Chance's stage and musical persona were finalized by romantic partner and agent Anya Philips, who died of cancer in 1981. Subsequently Chance's withdrew from public visibility for over a decade, before reappearing in the mid- 1990s.