My Idea is that you can select in the Flight Shedule, Time for Gates, in which the Stand is reserved for flights which can’t be handeled on the planned Position because of delay.
I think added to that the flight scheduler needs some work. My main issue is that even with separation, that separation only applies to the gates themselves so you end up with 10 planes landing at the exact same time requesting the same services which overwhelms most of my airports. So standby gates for delays with better flight separation could really make things run more smoothly.