Are the two parts in the same staff notated in the same layer (= two noteheads on the same stem)?

Or are the two parts in two different layers? Like S in Layer 1, and A in Layer 2?

when parts are unison, there's 1 note with stems running up and down; otherwise there's layer 1 and 2 for the men's and women's parts, respectfully. So I want to go from a hymnal-looking all singers parts on 2 staves to each vocal part on their own staff. Does this make sense to you?

… I'm writing a choral piece using a treble and bass clef for the singeres,  but need to convert to each voice having its own part (4 individual staves) …

If I understand you correctly, you need to convert the entire document to 4 staves - right?

I would add the needed staves, then copy music to the staves.

A useful command is Show Active Layer Only (in the Document menu).

Show Active Layer Only also means Edit Active Layer Only.