Original sentence: Kathleen Nott became involved in the writers' organisation  PEN in the 1950s, becoming editor of the organisation's journal, Bulletin of Selected Books (later renamed PEN International), in 1960
Edited sentence: Kathleen Nott became involved in the writers' organisation  PEN in the 1950s, becoming editor (initially acting editor  ) of the organisation's journal, PEN Bulletin of Selected Books (later renamed PEN International), in 1960