Following in the footsteps of Lincoln Center, another one of the city’s main performing arts venues is getting a massive makeover. City Center at 131 West 55th Street between Sixth and Seventh avenues announced this week that it will undergo a $75 million renovation, designed by Polshek Partnership Architects. Although the interior upgrade plans — such as a new layout and new canopy — have already been made public, City Center, a landmarked venue, must first complete an approval process from the Landmarks Preservation Commission before it can sign off on any exterior changes. The project, which will be completed in two phases, will begin in late April.