may take a look at this vedio, during this part, showing how to remove the ballast:https://www.youtube.com/watch?v=VXFisvd7FrI
no matter you are replace the 4-pin CFL with LED E27 or CFL E27, you need remove the ballast.
use this converter:http://www.amazon.com/gp/product/B00XVR2YG2