You can simply change the invoice due date by replacing the initial invoice.
In order to do this proceed as follows:
1. First open the transaction and click on details of the invoice.
2. Click on Actions > Replace:
3. Change the due date of the invoice.
Please note with the invoice replacement you can also change the prices and invoice details.
Once the invoice is stored, a new invoice will automatically be created.
Make sure to check if the new invoice was delivered to the customer.