I created a polysurface by Boolean several surfaces (tried “mergesrf” for this, didn’t work).
Now, I want to work with this polysurface (rebuild etc.) so I need to turn it into a surface.
MergeSrf only works with untrimmed surface pairs, if they are trimmed edges it won’t work. I would need to see the surfaces in question to know if this would help but you may try Untrim on the trimmed edges and then be able to MatchSrf and finally MergeSrf to get to a single srf. Usually remodeling as a single srf can be faster than this though. If the goal is to control point edit the model, I would consider CageEdit on the polysrf instead.
Shir, maybe you just need to explode your polysurf, or extract surfs from it.