Toggle Between Attack 1 & Attack 2 On Button Press?

You know how picking up a tree with a mountain giant toggles attack type from 1 to 2 or vice versa when he loses his tree? well is there a way toggle this manually with no trees by simply activating a spell on button press?

use any form shift (druids) with instant cast with cloned units.

Yep like said, use a tranformation in which each form has a different attack.