From the Aptean CRM Setup Page

Aptean CRM  •  Article  •  4/3/2023  • 
  1. Open the Aptean CRM Setup page either from the Setup menu on the Role Center page or from the search box.
    Refer to the From the Aptean CRM Setup page topic in the Synchronization for Contact and Company Details section for more information.
  2. On the action bar, select Send Sales History > Send Credit Memos to send all the posted credit memos to the Aptean CRM application.

If you are sending multiple records, the synchronization might take some time to complete.