Fleshcrafting is the process of consciously directing the healing process of wounds through haematurgy to alter the new flesh into something different to its original form. Simple applications of this may be to alter one's skin colour of facial features, while more involved and committed fleshcrafters might totally redesign the physiology of parts of their body, or the whole in very tightly-controlled situations.
In order to craft one's flesh anew, the old area must be a blank slate for new blood to fill in and be moulded. This involves totally removing the old flesh that is to be replaced - if fleshcrafting a new finger in place of one broken and arthritic, this would involve severing the finger.
In modern times, medical nanites assist with most fleshcrafting procedures to speed up healing, sculpt the desired areas, and minimise infection. Nanotechnology is also sufficiently advanced that they can carry out procedures with the same permanent effects as fleshcrafting, without the need to wound the subject, instead altering the selected area or whole body over time.
Transmutation is a special application of fleshcrafting, but involves a bloodbond with and materials from a second individual to carry out, and was until recently carried out mostly by those of the beast covenant.