All you need to do is to remove the corners of the cracks to smoothen the crack area with the help of a chisel knife.
Then fill it with soft paste of filler material so that the entire crack is filled, and the area looks smooth and seamless.
Remove the excess filler material and sharpen the edges so that the coving returns to its original shape, and there is no excess filler material popping out of the wall.
Clean the coving area with the help of a cloth to remove dust and any other impurities. Once the Coving looks clean and smooth, paint it using the color of your choice.