if you are using upgrades you wont be able to decrease the attack range anymore.
Events
Unit - A unit Learns a skill
Conditions
(Learned Hero Skill) Equal to (Your ability here)
Actions
Player - Set the current research level of (Improved Bows) to (Level of (Your ability here) for (Triggering unit)) for (Owner of (Triggering unit))
Events
Unit - A unit Learns a skill
Conditions
(Learned Hero Skill) Equal to (Your Ability)
Actions
If (All Conditions are True) then do (Then Actions) else do (Else Actions)
If - Conditions
(Level of (Your Ability) for (Triggering unit)) Equal to 1
Then - Actions
Unit - Set (Triggering unit) acquisition range to 750.00
Else - Actions
If (All Conditions are True) then do (Then Actions) else do (Else Actions)
If - Conditions
(Level of (Your Ability) for (Triggering unit)) Equal to 2
Then - Actions
Unit - Set (Triggering unit) acquisition range to 850.00
Else - Actions
If (All Conditions are True) then do (Then Actions) else do (Else Actions)............................
Sadly you can't alter a units aquisition range through upgrading or a trigger, only the attack range.
If you set the Acq range to 9999 it will attack any enemy on the map.
If you set the Acq range to 1 and the range to 20000 it will only attack a unit on command.
The only way to alter it is with a second unit.