There should be an explicit function called Create a Copy. The copy will be identical to the original, but not tied to the original in any way.
In these examples, one can not only solve the inversion problems by the method of explicit function, but also make the calculation simple and the result accurate.
There is no explicit function for making a copy of, or archiving, a document. Users must accomplish this with the Save As dialog, and doing so is as clear as mud.