The ability to change colors can be a useful tool in image processing. Given an m x n x 3 array (much like CData in images), find all instances of a specific color (c1) and change those pixels to another color (c2). Both colors are inputs to the function. The output is the modified 3D array. If there are no instances of the color to be changed, the output will be the same as the input 3D array.

Assume the class of all colors is double. So, for example, black is [0 0 0] and white is [1 1 1].