Complex sentence: He declined to run for a second term, and was succeeded by his deputy Thabo Mbeki, subsequently becoming an elder statesman, focusing on charitable work in combating poverty and HIV/AIDS through the Nelson Mandela Foundation.
Split into simpler sentences: He declined to run for a second term, and was succeeded by his deputy, Thabo Mbeki. Mandela subsequently became an elder statesman, focusing on charitable work in combating poverty and HIV/AIDS through the Nelson Mandela Foundation.