Was going to answer, then saw it is a Genesis 2 figure so, maybe the usual approach may not work; but this is the way to get to the settings panel in Poser ( I don't know which version you're using, but mine is currently Pro 11:

Click on the little right-pointing arrow in the specific morph line in the parameter tab. A menu pops up. Click Settings, and the settings window opens up. You can change the limits there.

Eternal Hobbyist