Each of the Transform tools (Rotate, Scale, Perspective, etc) can be set to act on a layer, selection, or path. Select the transform tool in the toolbox, then select layer, selection, or path for the Transform option in the tool's Tool Options dialog. This gives you a powerful set of methods for altering the shapes of paths without affecting other elements of the image.

By default a Transform tool, when it is set to affect paths, acts on only one path: the active path for the image, which is shown highlighted in the Paths Dialog. You can make a transformation affect more than one path, and possibly other things as well, using the « transform lock » buttons in the Paths dialog. Not only paths, but also layers and channels, can be transform-locked. If you transform one element that is transform-locked, all others will be transformed in the same way. So, for example, if you want to scale a layer and a path by the same amount, click the transform-lock buttons so that « chain » symbols appear next to the layer in the Layers dialog, and the path in the Paths dialog; then use the Scale tool on either the layer or the path, and the other will automatically follow.