By Abhinav Parmar and Lisa Baertlein (Reuters) -United Parcel Service posted better-than-expected results on Tuesday, in an early sign that the company's overhaul, which included cutting 48,000 jobs, was making headway following several difficult quarters of weak volumes. UPS shares rose 12.1% in premarket trading, with rival FedEx also gaining 3.2%. UPS shares are down about 28% since the start of the year. The profit beat and the forecast signal progress in UPS' efforts to rebuild margins and stabiliz ...