You can't on basic machines
M19 rotates and locks the spindle in a pre-defined orientation ready for toolchange.
M5 will release the orientation, enabling you to turn the spindle by hand
M19 stated again without any manual movement will only lock the orietation in the same place ( no rotation of the spindle )
M19 stated after turning the spindle by hand will allow the spindle to orientate back to it's pre-defined spot
( this orientation setting a no play area, as fooling with values will crunch the machine when it toolchanges)
On special optioned machines
it is posible by M19 D0, M19 D180 as an example
the machine must have the options fitted and are usually found on multi-tasking milling and turning centres, mill/turns etc.
I assume you are still working on trying to gauge part features