Since a toa can manipulate their element whether it is made of protodermis or not can they transform it from one to the other like a toa of water turning liquid protodermis into regular water?
Yes they effectivelly can. First they absorb one form of the element, converting it into elemental energy, then they release it in the other form.
Creating water/Liquid Protodermis
- Forming objects out of water
- Manipulation of water/Liquid Protodermis or moisture
- Drawing water out of the atmosphere
- Absorbing water/Liquid Protodermis
This would only work one way. While a Toa can control both types of their Element, they can only create the protodermis-based version:
At least in the case of Iron, the answer is no.