It seems the natural choice for a cvx to cnv conversion would be to re-save various versions of Canvas drawing. The latest versions of Canvas should be able to work with both .cvx and .cnv files just fine and can transform to another and vice versa.
Convert Canvas drawing to Canvas drawing.
We have found one software suitable in our database for this conversion.
Microsoft Windows software - convert cvx to cnv on Windows
A drawing software used to create technical illustrations and graphics
Convert from cvx file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.