Changing current customer on an overdue invoice

Changing current customer on an overdue invoice

I am trying to change a group of overdue invoices from "Company A" to  3 subgroup companies that were recently created (company 1, company 2, company 3). When I attempt to change the customer from "A" to "1", using the edit menu on the invoice, the ZOHO system claims that the changes were made but the invoice remains as Customer "A". Any thoughts on how to fix this issue?