Creo Interactive Surface Design (Style) > Curves > Editing Curves > To Unlink Curves and Surfaces
  
To Unlink Curves and Surfaces
Use this procedure to remove optional references from selected curves and surfaces.
1. In the Model Tree, right-click the Style feature that contains the curve to unlink, and choose Edit Definition. The Style tab opens.
2. Select one or more curves or surfaces to unlink.
3. Click Style > Unlink. You are asked for confirmation.
4. To complete the operation, click Yes. To cancel the operation, click No.