Faced with sagging sales and profits, Liz Claiborne Inc. said yesterday that it would eliminate about 400 jobs, close 30 retail stores and try to improve its ailing business at department stores. The company, the New York-based women's clothing maker, said the restructuring would cost $13 million to $17 million and would reduce the company's fourth-quarter earnings by 20 cents to 26 cents a share. The shares rose $1.3125, to $32.125. The price has slumped from more than $50 this summer.