Unplug the refrigerator or shut off the circuit breaker for the refrigerator. If the ice maker is overflowing (cubes over-sized and formed together), first try to adjust the water set screw. You'll need to remove the ice maker to get to access the set screw, which is on the ice maker module.
Turning the set screw clockwise decreases the water fill. 1/2 turn = approx 20cc of water. No more than one full turn in either direction or damage to the module could occur.
If that doesn't solve the problem, you would need a new ice maker module or complete ice maker assembly.