How do I Reattach a Sketch?
Reattaching a sketch serves 2 purposes. The first is for repairing sketches that have lost the plane that they were once attached to. The second is for relocating sketch based features elsewhere on your part. Either way utilizes the same method. On the sketch that needs reattaching, right click on the sketch in the browser and choose "reattach sketch". Then you select the face that it needs to be reattached to. The feature and sketch will become located on the new face. You will lose any constraints or dimensions that connected the sketch to model edges on the original sketch. The newly placed sketch can then be edited and relocated with constraints or dimensions.