This message indicates that there are two or more constituent records in Luminate Online with the same Member ID. In order to make any update to any of the records, the member ID would need to be unique. You can find out which record in LCRM is associated with the Member ID by referencing this article.

Once you know which LO constituent record is associated with the LCRM record, contact Support to have the Member ID of the non-associated record removed. After the Member ID becomes unique to only one Luminate Online record, you can then successfully perform the edits.