Rainbowgirl, while it is impossible for you to "morph" as the original poster puts it, the only reason that it is impossible for you, is that you believe it to be impossible therefore for you it is impossible.
The very first ingredient you MUST have for any spell to work is belief that it will work. Without that belief you can never channel the energy correctly to have the desired outcome.
Pixa, Belief is the key to all magick, without it things are impossible. Not that I am trying to argue with you, as I am not. I am sure most on this site would agree with you and therefore it is impossible for you and those that agree.
Now as for myself, I have never tried to shapechange, and I do not have the inclination to try, but for sake of the discussion let's say I did try and failed. My failure would not show that it is impossible, it only shows that I was unable to do it, nothing more. Therefore the possibility still exists.
I know of a man that was told my multiple doctors his eyesight was gone and there was no means, including surgery, that he would ever gain his eyesight back. 20 years after he could see again, he did not believe it was impossible and he did regain his eyesight. This is not some fake story posted on some obscure website, it is well documented by the Nichiren priests in Japan.
I was in a situation where I wanted an item to work in a certain way. Not magical, but mechanically. All the experts told me what I wanted was impossible, but I disagreed. It took me several years and more failed attempts that I can remember, but in the end I was able to design and build the item and have it perform exactly how I was told by the experts that was impossible. Sorry but I can't be more specific on what this item was as it would, within the right circles, give away who I am and I am not comfortable with the thought that people I work with or for, along with acquaintances know I practice magick. that is something only my closest friends know about and I plan to keep it that way.
Once again, someone with this word "Impossible". Maybe I am not coming across well enough, so I'll try again.
Belief is necessary for any magick to work, belief is the first and sometimes the hardest step to take, without taking this step everything will be impossible for you.
But belief is not the only step and depending on what you are trying to do there could be anywhere from a couple to several hundred step that must be taken to achieve your goal and each of these steps must be taken with all the conviction in your heart that you believe it possible.
I agree with nuuan belief is what you need to get your desired outcome on spells. like for example with one of my practice friends she didn't belief in herself so she didn't get what she wanted