You can indicate in the CRM of Akti that the invoices for this customer should actually be formatted to a third party. When creating an invoice to the customer, Akti will then ask you if the invoice should be formatted to the third party or not.
To start this, you go in the account sheet of the CRM to the tab "Financial". Here you have at the bottom right the option to activate third party invoicing for this customer and you can also define the third party. So this is another account from the CRM. Don't forget to click on save at the bottom of the page after you have made the adjustment.
When you now create an invoice for this customer (standalone invoice or from another Akti document), Akti will indicate in the editing screen of the invoice that this customer is invoiced to third parties and you can apply this invoicing as well. You have to confirm this adjustment and then this will be applied. Hereby the account on the invoice is thus overwritten and the VAT regime of the third party is applied to the invoice.