Complex sentence: He conducted separate negotiations with the union and with management, and proceeded to have proxy battles with shareholders and management until abandoning all efforts to buy the company out on January 8,1987, a few weeks before union employees returned to work.
Split into simpler sentences: He conducted separate negotiations with the union and with management, and proceeded to have proxy battles with shareholders and management. But he abandoned all efforts to buy out the company on January 8,1987, a few weeks before union employees returned to work.