Go to the "Prebook Product" from the configuration.

Tree view of the "Prebook Units".

In the product variant form view, you can see that the variant is currently in the “Allocated” stage.

Create a quotation and assign a salesperson.

Click on the product and search for it in the wizard.

Here you can see that the "TEST PRO" product variant is in the "Available" stage.

Tick the “Not Released” checkbox. The product variant will now move to the “Not Released” stage.

Click on the "Block Variant" button.
Enter the reason in the wizard and click on the “Confirm” button.

To unblock the variant, click on the “Unblock” button.

Create an SO for the "TEST PRO" product variant.

Here you can see that the "TEST PRO" product variant has moved to the "Reserved" stage.

Create a quotation and search for the "TEST PRO" product variant.
The variant is not found because it is currently in the "Reserved" stage.

In the list view of “Probook Units”, add the product variants that you want to reserve.

In the scheduled actions, click on the “Run Manually” button.

Here you can see that all the product variants have been removed and are now available.

Here you can see that the product variant is now in the “Available” stage.