SAP Message UPF027 - You must specify the fields to be changed for planning function &1

Diagnosis
You have attempted to create or save a planning function but you havenot specified which data is to be changed by the planning function.This error also occurs if, immediately after creating a new function,you attempt to create a new parameter group before the requiredspecifications for the planning function have been made. The definitionof the planning function is incomplete.

Procedure
Specify at least one field to be changed by the planning function.