Blacklisting lets you stop issued licenses from working in future versions of your application, normally to allow users to move licenses from one host to another.
To revoke an existing license, set the flag LMX_OPT_BLACKLIST, described in LMX_SetOption). When an application performs a checkout of a blacklisted license, it will return LMX_BAD_KEY.
For more about blacklisting and rehosting a license, see the Knowledgebase article, "Rehosting or blacklisting a license."