I loaded stock we received from a supplier as "normal" stock. How to I change this to stock so that is on consignment?

I have the steps to record the outgoing inventory as a consignor, Olivier. 

You can add your inventory items as well as other products and services you sell into QuickBooks. This lets you quickly add them as line items to your sales forms. The steps to add inventory, non-inventory, and service items are slightly different. 

Follow the steps to add inventory items. These are products you sell that let you set and track product quantities.

Then, proceed with setting up consignment income accounts in the Chart of Accounts (COA) to help track consignment sales and payouts. Now, you are ready to set up the consignment sales item. 

To make sure you won't miss a single step of the process, you can check this article: How to record consignment sales. Also, when running reports for a consignment, you can check the articles below for more details:

• Customize reports in QuickBooks Online.
• Common custom reports in QuickBooks Online.

Don't hesitate to post again if you have follow-up questions. I'm right here to help and guide you further. Take care and stay healthy.