change unit height with trigger

does anyone happen to know how to change units "flying" height with trigger?
i remember i saw it once before but i cant find it anymore? can anyone tell me where that trigger is?

PS: I AM NOT ASKING FOR HOW TO SET UNITS HEIGHT IN OBJECT EDITOR.

Unit - Set unit flying height

And that will only work for units with fly movement, also rate is the height per game time second the unit will go up/down