Skipping Invoices
From WHMCS Documentation
Occasionally you may wish to skip an invoice, giving the customer the invoiced period at no charge, but resume charging on the next due date.
Skip an invoice
If an unpaid invoice already exists, you can do this by performing the following steps:
- If an unpaid invoice already exists, you must first cancel that invoice:
- Go to Billing > Invoices.
- Click the invoice.
- In WHMCS 8.9 and later, click Manage Invoice.
- Click the Mark Cancelled.
- Go to the service that you wish to extend at no charge.
- Set the Next Due Date value.
- Click Save Changes.
The system will create the next invoice on the new due date without charging for the period between the old next due date and the new next due date.