I've built a cross table in Spotfire with some data which is aggregated in various ways (e.g. "sum", "first", etc.).
The default headers are really ugly (e.g. "SUM(revenue)") and I would like to change them to something a bit more relatable. For example, instead of SUM(revenue), I would like to have "Total Revenue".
For the example you gave in your question, just add the bolded portion below in the Custom Expression editor:
Sum(Revenue) AS [Total Revenue]
With several columns, it would be: Sum(Revenue) AS [Total Revenue], Sum(Expense) AS [Total Expense]
...and so on. You can also include special characters in your title as long as you're using the brackets