Complex sentence: On January 28,1977, a New York charter was made, forming the corporation of Joint Diseases North General Hospital, and in 1979, when JHD moved downtown, the Joint Diseases North General Hospital became the new occupant in Harlem.
Split into simpler sentences: On January 28,1977, a New York charter was made, forming the corporation of Joint Diseases North General Hospital. In 1979, after HJD moved downtown, the Joint Diseases North General Hospital became the new occupant in Harlem.