Diagnosis
You have attempted to delete a field from the definition of theplanning function. However, this field is still being used in at leastone of the function's parameter groups. As long as this is the case,you cannot delete the field from the planning function.

Procedure
Delete the field from all the function's parameter groups. For example,do not enter any more conditions for it.
In some cases, it will be necessary to delete the parameter groupsconcerned. To do this, you will have to terminate the planning functionmaintenance.