Hello Macaila Beynon,
What you are dealing with here is a licensing constraint in Microsoft’s ordering system. Client Access Licenses (CALs) can only be stepped up according to the rules defined in the Volume Licensing Service Center or CSP portal. A “step-up” order is restricted to certain paths, meaning you cannot arbitrarily convert Task CALs into Enterprise or Functional CALs unless Microsoft has defined that as a valid upgrade path. That is why the portal is blocking you from making the change.
In practice, this means you will need to purchase new Enterprise CALs and Functional CALs outright rather than attempting to step up the existing Task CALs, unless your licensing agreement explicitly allows that conversion. Microsoft licensing is strict about CAL types because they map to different feature sets and compliance requirements. The correct approach is to contact your licensing provider or Microsoft Volume Licensing support and request confirmation of the permitted upgrade paths. They can validate whether a step-up SKU exists for Task CALs to Enterprise or Functional, and if not, advise on the correct purchase.
I hope you've found something useful here. If it helps you get more insight into the issue, it's appreciated to accept the answer. Should you have more questions, feel free to leave a message. Have a nice day!
Domic Vo.