MC2 keeps a cache of processing rules. To reinit the rule cache the REST endpoint with offset 206 (default port 20426) should be used:
http://appserver:20426/services/eagle/v2/commands/reinitrulecache
This will reinitialize the rule cache for all MC2 instances with the same AppID.
This endpoint is available only from the application server.
There is another way to reinit the rule cache by using SOAP request or executing eagle_ml-2-0_extract_service_control_message stream.
It works in the same way as restart MC2 except that different commandType RTR task parameter and HTTP header are used and that any users have access to reinitialize the rule cache.
See information about restart MC2 here.