Ending Suppression
At the beginning of a player's turn, any unit that is Suppressed may make a Leadership test. If it passes, then it is no longer suppressed. It may then act normally.
Geek Notes
I considered allowing units to automatically shed Suppression after a turn. I discarded this idea, because I realized that Units Suppressed in an enemy's Firefight would then immediately recover! I think the randomness of the Leadership test makes Suppression more important and scary.