Answer by taking a quote from the following article:

Kevin Sydney is a fictional character appearing in American comic books published by Marvel Comics. The Changeling has been depicted as a member of the X-Men. Created by writer Roy Thomas and artist Werner Roth, the character first appeared in The X-Men #35 (August 1967). Kevin Sydney first appeared as Changeling, a mutant shapeshifter.

Kevin Sydney is a mutant metamorph with the ability to alter his physical appearance and voice at will to resemble that of any person he chooses. His power could also transform the appearance of his costume as well, which was made of unstable molecules. Morph's mutation to shape-shift has also made it so that his body is a Play-doh-like substance and he can reattach limbs after they have been severed. He has limited telepathic abilities, which (in the original timeline) were enhanced by Professor X. As a side effect, he also gained limited telekinetic abilities. Upon choosing to work together and share his body with the energy mutant Proteus, Morph's powers appear to be amplified, at least enough to defeat a self-proclaimed god. Whether the two have access to Proteus' reality changing abilities has yet to be determined.  He has also stated that his mutation gives him a high metabolism and makes him very hormonal. In Exiles #33 Sasquatch said she was never able to detect a scent on Morph and Sabretooth stated that while hunting Proteus in Morph's body, Morph stands out like a sore thumb in a crowd of "normal" people to Sabretooth's senses regardless of his form. It also appears he has the ability to fly as demonstrated in Exiles #27. Due to his shapeshifting ability he does not wear any actual clothing, and he takes joy in pointing this out.  Kevin Sydney is a skilled actor, and a highly trained and efficient organizer of subversive activities. He carried various advanced weaponry of alien Siri design belonging to Factor Three, including a ray gun carried in a holster at his side. Though Morph is a prankster who downplays his intelligence, he is deceptively smart. He has a Master's degree in computer engineering, which he earned at Xavier's Institute.

Did he ever lose any of his powers?