As famed Feinstein’s at the Loews Regency winds down for the hotel’s planned renovation, real estate brokers and “Selling New York” stars Tom Postilio and Mickey Conlon hosted a bash for VIP clients. Michael Feinstein performed a private show of Gershwin tunes for guests including Tyne Daly and “Law & Order: SVU” star Tamara Tunie. The room buzzed when Joan Collins — who performed her own one-woman show at Feinstein’s in 2010 and whose Midtown apartment was just featured on the HGTV series — arrived. Feinstein’s recently told us they were weighing options to continue at a new location, but nothing has yet been announced.