Here's how to do it:
- Go to the 'Data' pane.
- Click on the three-dot menu next to the table.
- From the menu, select 'Expand all'.
- Select a field and click on the three-dot menu next to the field.
- Select 'Rename'.
- Enter your custom legend label.
- Following these steps updates the name everywhere the field is used unless it's been overridden elsewhere.
