Some years back I asked Mike Eagleshield, then the head gunsmith at CZ-USA, whether it could be done.
He said probably, but it would take some serious gunsmithing and a good bit of money, as the decocker models are made subtly differently than the safety-equipped models. Parts alone would be expensive. (Little things like the detent on the safety, which is inside the frame, isn't needed on the decockers, and something would have to be fabricated. The decocker models have a hammer-hook removed to make room for the decocker mechanism, and that might mean you'd want a new (maybe after-market) hammer. I'm sure there are some other minor differences.
If you want a safety model, your best course of action is to trade with someone who wants what you have, or sell it outright and buy what you want.