To change the text in any table element (title, spanner, column head, stub, etc.) double click on the text you want to change. In the example below the table title has been selected.

You can now change the text of the table title. If you want a second line of text, press Ctrl+Enter to create a new line of text.

To go back to the original default text, right click on the text you want to change, select Format (table part), uncheck the Custom Text check box, then press OK.