I guess the question is a little vague. What do you mean "by change fans over"?
CM 212 is a decent heatsink, but it is quite tall and doesn't fit in all cases. Changing out a CPU fan is as simple as removing the old one, cleaning the CPU heat spreader with a non-abrasive and lint-free material and some rubbing alcohol. (Coffee filters are popular, cotton swabs, lens cleaners)
Follow the instruction guide for the new cooler. In the case of the Hyper Evo 212 you might want to look to YouTube. The included manual is a bit vague.
Then you just plug in the fan wires to the CPU fan header.