Placing Resource Upgrade order leads to an error:
It is prohibited to Upgrade/Downgrade Resources which are not installed; such as res.name (#1000108). Error Code: 0xb6b45990. Report ID: xxx
Resource in subscription has status "Purchased". Can be caused by the fact that subscriptions was created by API and resource was not physically provisioned.
Another reason for resource to be in "Purchased" status is that corresponding resource rate has been added to the Service Plan after subscripitons creation, and subscription has been synchronized with the plan with the option "Install to provisioning system" set to "Not install".
Synchronize this resource with Service Plan at first. It will get status "Optional" or "Installed".