I think so. But I have never done it.
On Windows, you should find Uninstallers for St4 and st3 in the Start Menu > All Programs > ... Not sure where they are on OSX. Unauthorize them in IKPM first.
But the best thing to do is
contact Support, via here. There is a link at the top of the Search FAQs page to the Technical Support form, for some one to one guidance.
Response time aims to be within 2 working days (US (East Coast) Business hours, generally), but in the current circumstances please allow some more time.