In case of changes, you normally want to explore more than 1 possible solution.
Then compare the options, and choose which solution will be implemented.
Using Windchill PDMLink as CAD archive holding limited object-iteration, some of them with state 'Released', in combination with Windchill PROJECTLink for the actual CAD activities (be it development or changes), this is very difficult.
The suggested PTC way of using a separate Project for each alternative works, but does not enable to compare the alternatives in the same CAD-session as the data is stored in separate Project,, using separate workspaces linked to separate CAD sessions.
Defining variant in the same Project comes down to making copies, which obviously makes it a very challenging activity to actually Send the chosen solution back to PDMLink as new iteration.
A functionality like 'branching' (as in Pro/INTRALINK 3.x) would be helpful. simply define branches, compare these, and finally choose which branch is the main branch.
Note that functionality like Design Exploration will not be relevant for tools like NX, SolidEdge, ...