To Rename a Symbol in the Library (AutoCAD Mechanical Toolset)

1. In the drawing area, double-click a symbol of the type of symbol library you want to edit. For example, to rename a symbol in the welding symbol library, double-click a welding symbol.
2. In the library, click the symbol to rename.
3. From the drop-down menu on the right, select Rename.
4. Enter the new name for the edge symbol.
5. Click OK.