If you want to change the data table header name.

Step 1

Change the required header name, for example change (Sales) to (Income)

Excel Data table with arrow | www.other-levels.com

Change Excel Data table Header names | www.other-levels.com

Step 2

Go to Data Menu > Click on Refresh All

Excel Data Menu, Refresh all | www.other-levels.com  

Step 3

Must re-add the new header name to the correct field in the pivot table

In the below example, here the Type has been added in the row's field,

and the Sales in values field.

Before chanage excel table headre name | www.other-levels.com

But after changing the name of the header from Sales to Income, the Sales will  removed from the values field,

So, you must add Income to the value's field

After chanage excel table headre name | www.other-levels.com