How did the constitution change reservation policies for a particular community in 1999 and how long did these changes last?
The constitution changed reservation policies for the Anglo-Indian community in 1999 by replacing the words "sixty years" with "fifty years" under the Constitution (Seventy-ninth Amendment) Act, 1999, s. 2 (w.e.f. 25-1-2000). These changes lasted until they were replaced by the subsequent amendments mentioned in the context provided.