You can reset your SoftRAID and MacDrive activation multiple ways.
1) Visit the License Management page on the OWC Software store and enter your serial number.
On the license information screen you will the status of your license, seat information, and the option to Deactivate seats. In the screen shot below, there are two seats to the license. One is available and one is active and can be reset.
2) You can also deactivate your SoftRAID or MacDrive installation through menu options.
Mac:
Windows: