When you set options for the Soft Modification Tool they affect the next soft modification you perform, not the current soft modification. It is recommended that you set the options prior to using the tool. If you want to edit options for the currently selected soft modification you can adjust the attributes on the softMod node in the Attribute Editor.
See the softMod command in the Maya Technical Documentation for softMod deformer node attributes.
To deform objects or components with Soft Modification
When Color Feedback is turned on you can view the area of influence of the Soft Modification tool.