If you want to make changes to a visualization that is linked to a master visualization, you must first unlink it from the master visualization. The visualization on your sheet is then independent with no connection to the master visualization in the assets panel.
Unlinking using 
A linked visualization can be unlinked using that is located in the top right corner of a linked visualization.
Do the following:
-
Click
Edit sheet. -
Click
in the top right corner of a linked visualization on the sheet.A dialog is displayed that you are about to unlink from a master visualization.
-
Click OK.
The visualization on the sheet can now be edited and the changes will not affect any other visualizations.
Unlinking from the shortcut menu
A linked visualization can be unlinked from the shortcut menu.
Do the following:
-
Click
Edit sheet. -
Right-click a linked visualization on the sheet.
The shortcut menu opens.
-
Select Unlink visualization.
A dialog is displayed that you are about to unlink from a master visualization.
-
Click OK.
The visualization on the sheet can now be edited and the changes will not affect any other visualizations.