Targeting and unloading swf

i used the follow code to load an external swf into a mc that is loaded into another mc where my main menu systen is.

loadMovieNum(“frame1.swf”,3);

how would i unload frame1.swf from my main mc. Keeping in mind the menu system is loading a swf at level 1 and that mc is loading frame1.swf into level 3

i can provide the site when my problem is located if anyone want to look