Change primary flag through HDL

When we change the primary assignment flag from one assignment to another one on the user interface - Employment info - and we then delete the the history where the new assignment got the primary flag, it automaticly also deletes the history from the first assignment, where primary changes to "no", so it knows there is a link between these 2 history lines

However, when we throuh HDL change the primary flag, from one assignment to the next one, and we then delete the history where the new assignment got primary flag on the userinterface, it will stil keep the history from the old assignment to primary "no", so in this case, there will be no primary flag