Complex sentence: Under Sublett, who was director of the W.K. Kellogg Foundation's National Fellowship and Leadership Program from 1991--2001, Kellogg Foundation the university has undergone major academic and structural changes, designed in part to respond to the issues identified during its reauthorization process.
Split into simpler sentences: Under Sublett, who was director of the Kellogg Foundation from 1991--2001, Kellogg Foundation. The Union has undergone major academic and structural changes, designed to respond to the issues identified during its reauthorization process.