creating a button which clears a UIloader from another swf file

hi;
so i have a main page called "main.swf", in this swf there is a button and a UIloader, when i click the button it loads another swf called "schedule.swf" on the UIloader.

now i also have another button on the "schedule.swf" which is suppose to clear the UIloader of the "main.swf". the problem here is that i don't know how to code that button for it to be able to clear the UIloader from the other swf.

i hope you got what i meant please help.