The space at 31 West 21st Street that housed Sean Combs' soul-food restaurant Justin's has been empty since 2007, but an agreement has finally been reached with Mark Stern, who bought it as a commercial condo. Stern, a partner in the now shuttered Village on West 9th Street, plans to morph the bilevel room into an upscale, 125-seat restaurant called Prandial (yes, as in "postprandial"). The restaurant, which is slated for a January opening, will have an old-world, stained white oak and mahogany bar and lounge with Chesterfield chairs, as well as a raised dining room on the first floor, plus additional dining space and a 40-seat private dining room on the second floor. "Each time we reached an agreement with the seller, he would decide to change the terms,'' said Eric Bates, Stern's attorney, explaining the spot's longtime vacancy. "The seller kept trying to get a better deal while he collected on Sean Combs' guarantee," says Stern. "We negotiated for over a year; it never would have happened but I had an amazing attorney.''