How to manually put one line on a multi line order on hold - and allow processing of the remaining l

I understand there are line level holds (M2=Margin Hold, PA=Product allocation Hold etc) but those are system created - so the user cannot put a line on hold manually.

In a user post "Hold code at line level" from 9/12/2013

Also read the FAQ document on Sales Order Holds (950782.1) - question 10 - which talks about PA hold which is defined at a line level basis code.

"However it should be understood that a Line Basis Hold puts the entire order on hold.

An order may be entered with 100 lines and only one of the lines triggers the Product Allocation Hold. It may