Complex sentence: In 2000, Sheppard Pratt retained the services HDR, Inc. to design a major expansion to the campus, which would be the largest addition to Sheppard Pratt since its inception.
Split into simpler sentences: In 2000, Sheppard Pratt retained the services HDR, Inc. to design a major expansion to the campus. The largest addition to Sheppard Pratt since its inception.