A 40-year-old old woman has multiple attacks of right upper quadrant abdominal pain after heavy meals. The last episode started after a fatty meal, colicky in nature radiating to the back and right shoulder lasting for 4 hours then gradually subsided with time and was associated with nausea, but no fever or vomiting. Her investigations are normal except for high serum levels of GGT and ALP with slight hyperbilirubinemia. Abdominal U/S reveals multiple gallbladder stones. What is the most appropriate next step in management?