Passing parameters to a running winxp service using command line

Question

I wrote a little service that blocks programs from running at a certain time of the day. For example, if I wouldn't want my brother from opening some games from 13:00 to 16:00. Everything works fine, but now, i would like to be able to set/change the time limits by writing commands from the command line while the service is running. If any of you can help me please or direct me to any sources that might help, please do. Daniel. BTW. The service is for purely educational reasons.