Yes you can deactivate a license. This will free it up for activation on another host. We sometimes get a scenario where an employee/contractor leaves the company, and in such cases the laptop/desktop they were using is usually re-imaged. If we are unable to deactivate studio before this happens then you must reach out to UiPath support to deactivate.
Depending on your Studio Version you will be looking at using
"C:\Program Files (x86)\UiPath\Studio\UiPath.LicenseTool.exe"
or
"C:\Program Files (x86)\UiPath\Studio\UiPath\Regutil.exe"