Definition of Reclassification Rules 
Purpose
When you define a
reclassification rule for a budget structure element, you are specifying in advance that the pay scale classification of this budget structure element’s budget is going to be changed.This means that you can transfer FTE from the budget of a budget structure element to another budget structure element whose budget has been assigned to a different pay scale.
This process describes how you can define reclassification rules for budget structure elements with FTE budgets.

You have a budget structure element with a budget of 5 pay scale 1 FTEs. Due to organizational restructuring, you now require only 3 pay scale 1 FTEs and 2 pay scale 2 FTEs. By defining a reclassification rule, you can convert (reclassify) 2 pay scale 1 FTEs into pay scale 2 FTEs.
You define customer-specific reclassification rules in Customizing.
Prerequisites
You must have made the appropriate settings in the following Customizing steps: Overall Budget ®
Budget Structure Element Types ® Define reclassification rules and Define Reclassification Rules Allowed for Specific BS Element Types.The status of the overall budget must be Proposed, Released, Released provisionally, or Being revised.
Process Flow

In the system, "defining" a reclassification rule is referred to as "creating" a reclassification rule.
See also:
Defining Reclassification Rules Activating Reclassification Rules Editing Reclassification Rules