This occurs when another user has checked out the update that is to be processed. While reviewing the transaction that is checked out, confirm the transaction Date/Status and see if the transaction is checked out by a user, and the username working with the update will be displayed under "Date/Status" column.  To resolve this, that user must log into The Rasier's Edge and check the transactions back in:
  1. Have that user log in to Raiser's Edge
  2. Open the Luminate Online (RELO) plugin
  3. Click the transaction link in question
  4. Unmark the box for the transaction in question or process the transaction
  5. If you unmarked the box for the transaction in question, close the transaction grid window, then click File>Exit & Sign Out
Please note:  If the user is no longer able to log into The Raiser's Edge (e.g. they are no longer with your organization), someone with Supervisor rights will need to change the password of the user in Admin >Security, log in as that user, and check the transactions back in.