The end user license agreement (EULA) for Native Instruments products allows the simultaneous installation on two computers (three computers for all versions of MASCHINE and KOMPLETE), as long as only one installation is used at any given time.
It is not required to unregister or deactivate your original activation in order to activate your Native Instruments products on a new (3rd or fourth - see EULA above) computer. However, it is required to uninstall the product from a previously used computer. Find more information on how to uninstall Native Instruments products in the corresponding articles for OS X or Windows. Please do not create a new account during this process. Always use the same login (your email address) to log into your account and handle your product activations. Learn more about Native Instruments user accounts in this article.
Note: Native Instruments reserves the right to disable an account or serial number if it has reason to believe that the end user license agreement (EULA) is violated.