With normal limewire you can't,

though I think pro lets you but I'm not familiar with it my advice if you have pro is to try to right click on the name and select delete(sometimes works with some programs) or try to go in the menus at the top and try to find a link saying this. another way that it might work is if you try it in options there might be a tab look under searches. Someone else might be able to answer your question try searching for this in the forums. but remember if you've got the normal one there's no way sorry for the bad news.