[Zubersoft]

Just press on the line and you can drag it up or down (if you are asking how to move the half page turn position). If you are asking how to avoid partial displays of staff lines, that depends on whether there is enough white space on the page where you can place the half page turn position without it cutting something off. If there is not, then you are correct that there may not be a way to prevent that, but you could just put the half page position lower on the page and turn the page ahead of time.

Mike