Load external SWF and unload external SWF

Hello,

I’m sure this question has been answered but I have been looking everywhere and all I can find is how to load an external SWF but not how to unload it. I come from a basic knowledge of AS2 and it was easy for me to load using levels but I have run into a wall. I have a main swf and to keep the initial filesize small I would like to split some image intensive sections out and load them when needed.

thank you for your help,
Gianfranco