In the Tools toolbar, select the Brush or Eraser tool.
In the Tool Properties view, click the arrow button to open the Brush/Eraser Properties dialog.
If you are drawing on a vector layer, set the Brush Type to Textured Vector if you are using the brush tool or the Eraser Type to Textured Eraser or Textured, Preserve Vector if you are using the eraser tool.
Select the brush tip you wish to rename.
Click on the Paper Texture menu icon and select Rename.
In the Rename dialog box that appears, type in the new name of the brush tip.