Tere Blanca, a top commercial real estate executive, is leaving Cushman & Wakefield’s South Florida office after more than five years to start her own firm. She is the current chair of Miami-Dade’s economic development group, the Beacon Council. Blanca, who announced the decision to Cushman & Wakefield employees late yesterday, said she is leaving the company to move from management back to deal-making. She will open her office in two months. She declined to discuss the details of the new venture but said the company would focus on commercial real estate, including office sales and leasing.