Users may find that removing the revenue category from a pledge record removes it from all payments towards the pledge.
Revenue Category items will be removed from pledge payments if the revenue category is removed from the pledge record itself. A better approach to recording information if this impacts users is to look at using Attribute Categories instead.
Steps to Duplicate
Open a pledge record that has more than one installment.
Click "Edit Pledge"
Change the Revenue Category to a new value or blank
Save the Edit Pledge form
Open the installment records and note that revenue categories have been changed on all installments