Changing the name of cell headers in the pivot table

Whenever I try to change the name of the cell headers in my Pivot Table I get an error message that says "Pivot Table Field Name already exists."

The headers say Sum of (because they're summing my data) but I don't want to read Sum of in my headers.

Any suggestions?

Thanks,
Matt

You can't use the name of an item that exists already in your table. You need to be creative and change the title so that it still is representative of the data but not already in the database...