This article describes how to go from a table like this...
...to a table where you change, for example, the NET row label to Total:
1. Select your table.
2. In the toolbar go to Automate > Browse Online Library > Modify Headers > Automatically Rename Row Labels.
3. Select the label you wish to rename in the Old label drop-down.
4. Enter the new name in the New label field.
While you can simply right-click a table category > Rename to change a label, this rule allows users to choose when to show this label without it flowing through to every other table that uses this question.
Note, if you select Swap rows and columns on your table, the rule will no longer work due to the table dimensions changing. In this case, you will have to apply the Automatically Rename Column Labels rule instead.