In your Windows Start button list of Programs you should have ProSeries 2018 in the list, in a sub list under it should be Uninstall.....but I don't see Uninstall for my ProSeries 2018 program either...its in all the other years.

I wonder if you can remove just the state using the Windows Settings > Apps & Features > click on  ProSeries 2018 and Uninstall (see pic)