All you have to do is go in to the SuperSU app>>settings and there is an option to fully unroot the device.
That worked for me and I was able install “Good” and other corporate apps on my phone.
Re-installing root may be a bit trickier though, although doing a “dirty” flash of the mirek ROM would probably work and still keep your apps and data. But, the tablet works perfectly fine without root so not sure why you would need it.
Thanks Stapo101 for your answer, i have done it this morning, and find it under SU. But i didn´t have time to update my post, and yes it works very well.
The problem is some app that need root, like adway to remove ads, does not work without it.
Anyone know an alternative to adway that doesn´t need root?