Unattach an upload from a Post

Hey all,

This may be a silly question, but I cannot see a way of doing it – how do you un-attach an upload from a Post? I have a list of PDF’s that were all attached to ‘Home’, but now I have created a template specifically for these PDF’s and I cannot seem to either un-attach them from ‘Home’ or attach them to ‘Brochures’ in addition to ‘Home’.

Any help is greatly appriciated.

Thanks.