There is no direct way to change the radius of a feature line, but there are a few workarounds:
-If the feature line is part of a sketch, you can edit the sketch and change the dimensions of the circles or arcs that make up the feature line.
-If the feature line is not part of a sketch, you can use the Break tool to create a vertex at the desired location, then move the vertex to change the radius.
-You can also use the Trim tool to trim the feature line at the desired radius.