Unscrewing and removal is a cinch. The real problem comes with refitting, as in many lenses the screws also hold the helicoid. But with some lenses, it can be quite simple, as I discovered with the CV 35/1.2 V1 and the ZM 28.
I'm not planning to replace the flange with a new one, simply to have pits for 6-bit coding to be milled in the most economical way possible.
I am aware of several DIY options, including the use of a dremel, but if I could easily remover and refit the flange myself, I would prefer to have the pits milled by John Milich in the US.