@mostlostnoob
Thanks, this works. I can drag the assist order to the factory itself, and the assist order will disappear after the current build order is finished. A bit awkward, but works.
@Sylph_
So if I have a factory assisting another one, and I want to upgrade the assisting factory to t2, if I cancel the assist order directly the current order gets cancelled and the buildtime and resources wasted. Unfortunately that command doesn't help.
I made the post after I saw that a half upgraded t2 factory was still assisting a t1 factory, and I didn't want it to spam out t1 units so I unassisted the upgrading factory, and lost half the progress.