SAP Message VL221 - Batch in item & already specified for material &

Diagnosis
The batch was either predefined in the sales order thatthe delivery is based on or it was assigned to the delivery itemmanually. Therefore, you can no longer carry out abatch split for thedelivery quantity of the items.

Procedure
In order to make the batch split possible, you can cancel theassignment of the delivery item to the batch, if the delivery'sprocessing status allows.