If you are running the Lightspeed Integration there is a preliminary step we recommend you perform. Log into Astro directly as an Admin, then lookup both of the accounts you plan to combine and remove the link to the account in Lightspeed by clicking the Incorrect Customer button located below the customer's name. Then once you combine the two accounts into one you can lookup the customer in Lightspeed and attach them to blank sale, click the Astro Loyalty button, find the customer account listed and click on it to recreate your LS>Astro link.