Ship Sets

We have ship to customers who regularly submit small, 2-3 line orders.  WE have ship sets turned on.  All this works fine.  However, occassionaly, these customers will submit a large 50+ line order.  These orders have ship sets.  In order to effectively release and pick these orders we have to remove all the ship set from all of the lines.  to do this we inquire on the order, go to lines, place our cursor in the ship set and then

(DELETE,DOWN ARROW) repeatedly until we reach the end of the order lines.  Removing "Ship" from "Line Sets" on the header does nothing and "Mass Change" does not work.