Right-click the unallocated space and select to reformat it to its original physical size.
Using SDATA Tool V1.0 is straightforward: sdata tool v100 double usb or sd card space exclusive
The developers behind the SData Tool V100 have hinted at a "Triple Space" update for Q4 of this year. However, currently, the remains the gold standard. The upcoming v2.0 promises: Right-click the unallocated space and select to reformat