Related Companies is close to signing a contract to manage sales and leasing at Muss Development’s new 3.3 million-square-foot Sky View Parc complex in Flushing, Queens, Crain’s reported. The development will set six residential towers and a rooftop park atop a three-story, 800,000-square-foot shopping center. The first three towers are almost complete, but Muss’ financial partner, private equity firm Onex, is said to be anxious about slow sales in the buildings and wanted a change. In a press release last year, Muss said 70 percent of the 448 condo units in the first building were sold, while 30 percent were sold in the second. Sales had not yet started in the third tower at the time. Retail space in the shopping center below had been 70 percent leased, with tenants including BJ’s Wholesale Club and Applebee’s Neighborhood Grill & Bar. Onex invested $66 million in the Sky View Parc project, and both Muss and Onex approached Related as part of a plan to get things back on track, sources said.