You should take a look at the Oracle Activate Pulsar Beam Weapon.
The way the Oracle does it, is by having a behavior added to the unit, that enables the weapon in the Modification of the Behavior - Buff.
You can add 2 weapons to a unit, set 1 to be Disabled in the Options of it. Then have a Behavior that disables the weapon that you already have active, and enables the disabled weapon. If you need clarification, I'll create a short tutorial to show you how to do it.
You should take a look at the Oracle Activate Pulsar Beam Weapon.
The way the Oracle does it, is by having a behavior added to the unit, that enables the weapon in the Modification of the Behavior - Buff.
You can add 2 weapons to a unit, set 1 to be Disabled in the Options of it. Then have a Behavior that disables the weapon that you already have active, and enables the disabled weapon. If you need clarification, I'll create a short tutorial to show you how to do it.