If you dialed the skill and no other enemy unit is at range to engage, ¿ the transformation is done or canceled?

Cancelled is my understanding. The first part of performing the skill is to put him engaged with an enemy unit. Since you can’t complete that step, you can’t proceed.

Others more detailed than I may shed some light if I’m wrong

I searched and couldn’t find anything on it either. In reading the card, it appears that the entire action is predicated on there being an enemy unit at range 1, so I would agree with @Church14 on this. However, after that goofy ruling on entering terrain at World’s anything is possible... 🤣

thnx.

Cancelled is my understanding too