Manage Conditional Formatting 

Allow you to see all the conditional formatting defined in the spreadsheet.

To access this function
Format > Conditional Formatting > Manage. 

The Manage dialog box opens. Here you can add, edit or remove one or several conditional formatting. 
If you have defined a conditional formatting on a cell range and you try now to define a new conditional formatting on a part of this range, a warning message will be displayed, asking if you want to edit the existing conditional formatting (on the whole range) or define a new conditional formatting overlapping it (on the selected range).