It’s shame, I cannot test it against an unusable action. It cancels forms when Soulshape is on CD, which is quite annoying due to GCD. Also, it is interesting when you use that macro on let’s say Catform and shapeshift into Soulshape. Then, when you use /cancelform it gets back to Catform
What is it you’re trying to accomplish? If you’re trying to cancel Soulshape you can do that just by casting almost any spell. If you’re trying to cancelform in order to cast Soulshape that’s completely unnecessary.
EDIT.
Just for everyone who has the same issue as I, there is the console variable autoUnshift, which controls if one can freely change forms. Essentially, in the file C:\Program Files (x86)\World of Warcraft\_retail_\WTF\Account\<your account>\config-cache.wtf change the line:
SET autoUnshift "0"
to
SET autoUnshift "1"
and it’s going to work. It’s 1 but default so one of my addons must have messed that. Thanks.