"To change the demographics" means to alter or modify the population composition or characteristics of a particular area or group of people. Full definition
The economic and racial makeup of most classrooms today fail to reflect the rapidly changing demographics of the nation. (americanprogress.org)
However, it has seen a decline in membership in the last decade, something officials blame partly on changing demographics in the area and the weak economy. (articles.chicagotribune.com)
The tenant - mix in the mall had failed to keep up with changing demographics. (nreionline.com)