External swf, getting back

G’mornin to all (UK here)
ok, so now I have an external swf which I can get loaded into my main presentation by applying a load movie action to a button but I just can’t get back to the original, I’ve tried unload movie but it does nothing. I have a (back) button on the external swf which i can obviously attach actions to but I don’t know what actions to apply, I’ve tried following a few tutorials to get my head around it but to no avail, do any of you flash gurus have any ideas. BTW I haven’t created an empty movie clip and loaded the external swf into it, all I have done is put the load movie action to a button. I’m sure it dead simple but for a flash noob it doing my head in, thanks already

edit: I have applied an unload action to the button on the external swf but it returns me to a blank white screen now, what am I doing wrong?