When you are working in batch and there are validation errors that do not allow your data to be matched against existing data (i.e. merged lookup ID is not matched against current lookup ID), we delete the rows; however, it would be ideal if we could export that data, provide new lookup IDs and then re-import. This would perform similar to the exception file when the file is imported. Ideally of course it would be great if "alternate IDs" could be picked up in batch