Not quite sure what you're after here? And how "late on finals"? And whether you're talking "possible", or the best way of doing it?
Having just come off the 757/767, and now on A320, the Airbus is a little quicker (button presses) to change runways in the box, and if such a change was anticipated, the "secondary Flt Pln" I find easier to use than whatever the Boeing box equivalent was...
However, if you're discussing less than, say 2000', and visual, can't see why anyone would even think of doing this on the box, and not disconnecting everything and look out of the window!
NoD