Hello there, @doug-leepa.
Deleting an invoice linked to an estimate will not reset the estimates' status to Pending. However, it will show as Accepted. You need not worry, you can recreate the invoice and link it to the same estimate. I can guide you on how to do it.
- Go to the Sales menu.
- Choose the Customers tab.
- Double-click on the name of the customer.
- Locate the estimate you want to work on.
- From the Actions column, click the Create Invoice link.
- Set how much do you want to invoice.

- Click the Create Invoice button.
- Review the invoice details.
- Hit Save and Close.
The estimate will show a Close status once you have completely linked it to an invoice. You can read through this article for more detailed instructions: Set up and send progress invoices in QuickBooks Online.
Always feel free to leave your comments below if you have other questions about managing and converting your estimates. I'm just a few clicks away.