From Heroes Wiki
Initially, Rene's ability was limited to the traditional sense of shape shifting. He could shift into different. With his enhanced durability he worked as a body double for celebrities, politicians, heads of industry.
Rene's ability is broader in scope than Shape Shifting, a Morpher can shape shift or morph at will into any shape he can conceive and has scanned via physical contact. The mechanics are not completely know as this ability is exceptionally rare. The user can draw additional mass from an unknown source when needed if he is morphing into something larger than his size. If the user is morphing into something smaller any additional mass is shunted into this same unknown source. Depending on what he becomes and the size his physical attributes change accordingly. He becomes an exact copy what he has morphed into with all its inherent abilities and flaws while retaining consciousness and intelligence when morphed into an inanimate object or animal. This ability affords the experienced user a limited form of invulnerability in so much that he can reform wounds and damage using the same mass he uses to increase his size and possibly a limited form of immortality.