I put together that actor I was describing earlier.

1.) Place the PropertyChanger in the map near the thing to be altered (the Counter) -- it's under Triggers
2.) Set the PropertyChanger's Event = Counter's Tag
3.) Open the PropertyChanger's properties and go to the PropertyChanger tab
4.) Set Property=NumToCount and Value=#
5.) Set the PropertyChanger's Tag = the Event of some trigger that you want to reset the Counter's countdown value (this trigger is the Resetter)
6.) Touch the Resetter and you will see that the Counter's NumToCount is back to the value you specified in the PropertyChanger

My instruction writing skills are in the toilet so check out the enclosed example map as well.