Sheesh. Couple of worrying posts here.
I would've thought it was cut & dried. Sure, if you're at or above the circling minima, you can break off and do a "circling approach" IAW the rules on how you fly a circling approach.
If you're below the circling minima (eg on a straight-in VOR/ILS or whatever) and you discontinue the approach, well you're in missed approach territory, end of story. And you don't fly "half" a missed approach unless for example you get radar identified and vectored, or you climb above an applicable MSA (as opposed to circling minima).
It's not that hard. Surely.