An East Amherst retirement facility is operating under new management and has changed its name to Solstice Senior Living. The Transit Road facility, formerly known as Montgomery Park, is among 32 independent living communities owned by NorthStar Healthcare Income Inc., a real estate investment trust (REIT). The new name comes via a joint venture with Integral Senior Living, a Carlsbad, Calif., company that manages independent, assisted living and memory care properties in 22 states.